diff --git a/Makefile b/Makefile
index e147140..56d2327 100644
--- a/Makefile
+++ b/Makefile
@@ -23,21 +23,71 @@
 # along with this program; if not, write to the Free Software
 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 # 02110-1301 USA.
+VERSION := 0.2
+PROJECT := davadmin
+SRCFILES := $(wildcard admin/*.php)
+APISRC := $(SRCFILES:,= )
+TEMPDIR := $(shell mktemp -t -d davadmin.XXXXXXXXXX)
+XSRCFILES := $(patsubst %,$(TEMPDIR)/%,$(SRCFILES))
+TRANSLANG := de
+POSRC := po
+POFILES := $(foreach lang,$(TRANSLANG),$(POSRC)/$(lang).po)
+MOFILES := $(patsubst %.po,%.mo,$(POFILES))
+POT=$(POSRC)/$(PROJECT).pot
+
+.PHONY: all
+all: $(POT) $(MOFILES) $(TEMPDIR)/delete
+
+$(MOFILES): %.mo: %.po
+	@echo "msgfmt: $@"
+	msgfmt -o$@ $<
+
+$(POFILES): %: $(POT)
+	@echo "msgmerge: $@"
+	msgmerge -U $@ $(POT)
+	touch $@
+
+$(POT): $(XSRCFILES) po/pot.sed
+	@echo "xgettext: $@"
+	cd $(TEMPDIR) && \
+	xgettext --default-domain=$(PROJECT) --language=php \
+	  --from-code=UTF-8 \
+	  --msgid-bugs-address="jan@dittberner.info" -o- $(SRCFILES) \
+	| sed -f $(CURDIR)/po/pot.sed \
+	> $(CURDIR)/$@
+	for pofile in $(POFILES); do \
+	  if test ! -f $(CURDIR)/$${pofile}; then \
+	    cp $(CURDIR)/$@ $(CURDIR)/$${pofile}; \
+	  fi; \
+	done
+
+.INTERMEDIATE: $(XSRCFILES)
+$(XSRCFILES): $(TEMPDIR)/%: %
+	@echo "processing: $<"
+	mkdir -p $(@D)
+	cp $< $@
+
+$(TEMPDIR)/delete:
+	rm -rf $(TEMPDIR)
+
 .PHONY: apidoc
-
-VERSION=0.2
-PROJECT=webdavadmin
-SRCFILES=admin/common.inc.php,admin/directories.php,admin/getgroups.php,admin/index.php,admin/users.php
-
 apidoc:
 	if [ -d apidoc ]; then rm -r apidoc; fi
-	phpdoc -f $(SRCFILES) -t apidoc --undocumentedelements on -s
+	phpdoc -f $(APISRC) -t apidoc --undocumentedelements on -s
 
-clean:
+.PHONY: clean distclean
+clean: $(TEMPDIR)/delete
 	find -name '*~' -type f -exec rm {} \;
 
 distclean: clean
 	if [ -d apidoc ]; then rm -r apidoc; fi
 
+RELPREFIX := $(PROJECT)-$(VERSION)
 dist: distclean
-	cd .. ; tar czf $(PROJECT)-$(VERSION).tar.gz $(PROJECT)-$(VERSION)
+	cd .. ; if test ! -d $(RELPREFIX); then \
+	  ln -s trunk $(RELPREFIX)-dev; \
+		tar czh --exclude=.svn -f $(RELPREFIX)-dev.tar.gz $(RELPREFIX)-dev; \
+		rm -f $(RELPREFIX)-dev; \
+	else \
+	  tar czhf $(PROJECT)-$(VERSION).tar.gz $(PROJECT)-$(VERSION); \
+	fi
diff --git a/admin/common.inc.php b/admin/common.inc.php
index 3b9949e..739a579 100644
--- a/admin/common.inc.php
+++ b/admin/common.inc.php
@@ -27,6 +27,9 @@
  * 02110-1301 USA.
  */
 
+/** Include common internationalization code. */
+require_once("i18n.inc.php");
+
 if (!isset($_SERVER['DavAdminConfDir'])) {
   header('HTTP/1.0 500 Internal Server Error');
   header('Status: 500 Internal Server Error');
@@ -79,7 +82,7 @@ function getFullPath($dirname) {
 $errmsgs = array();
 if (!isset($davconfig['digest.file'])) {
   array_push($errmsgs,
-             _("digest.file is not defined."));
+             sprintf(_("%s is not defined."), "digest.file"));
 } elseif (!is_readable($davconfig['digest.file']) ||
           !is_writable($davconfig['digest.file'])) {
   array_push($errmsgs,
@@ -87,7 +90,7 @@ if (!isset($davconfig['digest.file'])) {
 }
 if (!isset($davconfig['group.file'])) {
   array_push($errmsgs,
-             _("group.file is not defined."));
+             sprintf(_("%s is not defined."), "group.file"));
 } elseif (!is_readable($davconfig['group.file']) ||
           !is_writable($davconfig['group.file'])) {
   array_push($errmsgs,
@@ -95,7 +98,7 @@ if (!isset($davconfig['group.file'])) {
 }
 if (!isset($davconfig['namemap.file'])) {
   array_push($errmsgs,
-             _("namemap.file is not defined."));
+             sprintf(_("%s is not defined."), "namemap.file"));
 } elseif (!is_readable($davconfig['namemap.file']) ||
           !is_writable($davconfig['namemap.file'])) {
   array_push($errmsgs,
@@ -103,7 +106,7 @@ if (!isset($davconfig['namemap.file'])) {
 }
 if (!isset($davconfig['dav.dir'])) {
   array_push($errmsgs,
-             _("dav.dir is not defined."));
+             sprintf(_("%s is not defined."), "dav.dir"));
 } elseif (!is_dir($davconfig['dav.dir']) ||
           !is_readable($davconfig['dav.dir']) ||
           !is_writable($davconfig['dav.dir'])) {
@@ -112,11 +115,11 @@ if (!isset($davconfig['dav.dir'])) {
 }
 if (empty($davconfig['dav.realm'])) {
   array_push($errmsgs,
-             _("dav.realm is not defined."));
+             sprintf(_("%s is not defined."), "dav.realm"));
 }
 if (empty($davconfig['dav.uri'])) {
   array_push($errmsgs,
-             _("dav.uri is not defined."));
+             sprintf(_("%s is not defined."), "dav.uri"));
 }
 if (!empty($errmsgs)) {
   errorAsHtml(implode("<br />", $errmsgs));
diff --git a/admin/getgroups.php b/admin/getgroups.php
index 1690d12..59237f8 100644
--- a/admin/getgroups.php
+++ b/admin/getgroups.php
@@ -27,6 +27,9 @@
  * 02110-1301 USA.
  */
 
+/** Include common internationalization code. */
+require_once("i18n.inc.php");
+
 if (!isset($_SERVER['DavAdminConfDir'])) {
   header('HTTP/1.0 500 Internal Server Error');
   header('Status: 500 Internal Server Error');
diff --git a/admin/i18n.inc.php b/admin/i18n.inc.php
new file mode 100644
index 0000000..34500bd
--- /dev/null
+++ b/admin/i18n.inc.php
@@ -0,0 +1,144 @@
+<?php
+/**
+ * Internationalization code for DAVAdmin.
+ *
+ * @author Jan Dittberner <jan@dittberner.info>
+ * @version $Id$
+ * @license GPL
+ * @package DAVAdmin
+ *
+ * Copyright (c) 2007 Jan Dittberner
+ *
+ * This file is part of DAVAdmin.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301 USA.
+ */
+
+/**
+ * Gets the language data.
+ */
+function get_language_data() {
+  static $supportedLanguages = array();
+  static $defaultCountry = array();
+
+  if (empty($supportedLanguages)) {
+    /* English */
+    $supportedLanguages['en']['US']['description'] = 'English (US)';
+    $supportedLanguages['en']['GB']['description'] = 'English (UK)';
+    $defaultCountry['en'] = 'US';
+
+    /* German */
+    $supportedLanguages['de']['DE']['description'] = 'Deutsch';
+    $defaultCountry['de'] = 'DE';
+  }
+
+  return array($supportedLanguages, $defaultCountry);
+}
+
+function _setlocale($category, $locale) {
+  if (($ret = setlocale($category, $locale)) !== false) {
+    return $ret;
+  }
+  /* Try just selecting the language */
+  if (($i = strpos($locale, '_')) !== false
+      && ($ret = setlocale($category, substr($locale, 0, $i))) !== false) {
+    return $ret;
+  } else if (($i = strpos($locale, '_')) === false) {
+    list($languages, $defcountries) = get_language_data();
+    $locale = $locale . "_" . $defcountries[$locale];
+    if (($ret = setlocale($category, substr($locale, 0, $i))) !== false) {
+      return $ret;
+    }
+  }
+  /*
+   * Try appending some character set names; some systems (like FreeBSD)
+   * need this. Some require a format with hyphen (eg. Gentoo) and others
+   * without (eg. FreeBSD).
+   */
+  foreach (array('UTF-8', 'UTF8', 'utf8',
+                 'ISO8859-1', 'ISO8859-2', 'ISO8859-5', 'ISO8859-7',
+                 'ISO8859-9', 'ISO-8859-1', 'ISO-8859-2', 'ISO-8859-5',
+                 'ISO-8859-7', 'ISO-8859-9', 'ISO-8859-15',
+                 'EUC', 'Big5') as $charset) {
+    if (($ret = setlocale($category, $locale . '.' . $charset)) !== false) {
+      return $ret;
+    }
+  }
+  echo "unable to select a valid locale code";
+  return false;
+}
+
+function _get_supported_language_code($code, $fallback = true) {
+  static $supportedLanguages;
+  static $defaultCountry;
+  if (!isset($supportedLanguages)) {
+    list($supportedLanguages, $defaultCountry) = get_language_data();
+  }
+
+  list ($language, $country) = preg_split('/[-_]/', "${code}_");
+  $country = strtoupper($country);
+  if ((empty($country) || !isset($supportedLanguages[$language][$country]))
+      && isset($defaultCountry[$language])) {
+    /* Use default country if none specified or particular country not
+     * supported */
+    $country = $defaultCountry[$language];
+  }
+  if (isset($supportedLanguages[$language][$country])) {
+    return "${language}_${country}";
+  }
+
+  if ($fallback) {
+    return 'en_US';
+  } else {
+    return null;
+  }
+}
+
+function _http_negotiate_locale() {
+  $accepted = $_SERVER['HTTP_ACCEPT_LANGUAGE'];
+  if (!empty($accepted)) {
+    foreach(explode(",", $accepted) as $code) {
+      $languageCode = _get_supported_language_code($code, false);
+      if (isset($languageCode)) {
+        return $languageCode;
+      }
+    }
+  }
+  return null;
+}
+
+session_start();
+$project = "davadmin";
+
+if (isset($_GET["language"])) {
+  $languageCode = _get_supported_language_code($_GET["language"], false);
+  if (isset($languageCode)) {
+    $_SESSION["language"] = $languageCode;
+  }
+}
+if ($_SESSION["language"]) {
+  $language = $_SESSION["language"];
+} else {
+  $language = _http_negotiate_locale();
+  $_SESSION["language"] = $language;
+}
+putenv(sprintf("LANG=%s", $_SESSION["language"]));
+putenv(sprintf("LANGUAGE=%s", $_SESSION["language"]));
+$_SESSION["locale"] = _setlocale(LC_ALL, $_SESSION["language"]);
+bindtextdomain($project, realpath(dirname(__FILE__) . DIRECTORY_SEPARATOR .
+                                  ".." . DIRECTORY_SEPARATOR . "po"));
+textdomain($project);
+?>
\ No newline at end of file
diff --git a/po/davadmin.pot b/po/davadmin.pot
new file mode 100644
index 0000000..60920b0
--- /dev/null
+++ b/po/davadmin.pot
@@ -0,0 +1,100 @@
+# DAVAdmin.
+# Copyright (C) 2007, Jan Dittberner
+# This file is distributed under the same license as the davadmin package.
+# Jan Dittberner <jan AT dittberner.info>, 2007.
+#
+#, fuzzy
+msgid ""
+msgstr ""
+"Project-Id-Version: davadmin 0.2\n"
+"Report-Msgid-Bugs-To: jan@dittberner.info\n"
+"POT-Creation-Date: 2007-11-30 22:16+0100\n"
+"PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
+"Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
+"Language-Team: LANGUAGE <LL@li.org>\n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=UTF-8\n"
+"Content-Transfer-Encoding: 8bit\n"
+
+#: admin/common.inc.php:37 admin/getgroups.php:37
+msgid ""
+"The Server is not configured correctly. Please tell your Administrator to "
+"set the DavAdminConfDir environment variable."
+msgstr ""
+
+#: admin/common.inc.php:57
+msgid "Invalid call!"
+msgstr ""
+
+#: admin/common.inc.php:85 admin/common.inc.php:93 admin/common.inc.php:101
+#: admin/common.inc.php:109 admin/common.inc.php:118 admin/common.inc.php:122
+#, php-format
+msgid "%s is not defined."
+msgstr ""
+
+#: admin/common.inc.php:89
+msgid "The specified digest file is not readable and writable."
+msgstr ""
+
+#: admin/common.inc.php:97
+msgid "The specified group file is not readable and writable."
+msgstr ""
+
+#: admin/common.inc.php:105
+msgid "The specified name mapping file is not readable and writable."
+msgstr ""
+
+#: admin/common.inc.php:114
+msgid "The specified DAV directory is no directory or not accessable."
+msgstr ""
+
+#: admin/directories.php:114
+#, php-format
+msgid "%d kBytes"
+msgstr ""
+
+#: admin/directories.php:130 admin/directories.php:236
+#: admin/directories.php:275
+#, php-format
+msgid "Invalid directory name %s!"
+msgstr ""
+
+#: admin/directories.php:227
+#, php-format
+msgid "There already is a directory entry named %s, but it's not a directory!"
+msgstr ""
+
+#: admin/directories.php:286 admin/directories.php:307 admin/users.php:344
+#: admin/users.php:365 admin/users.php:369
+#, php-format
+msgid "Unexpected values %s!"
+msgstr ""
+
+#: admin/directories.php:303
+msgid "Delete failed!"
+msgstr ""
+
+#: admin/users.php:64 admin/users.php:84 admin/users.php:327
+#, php-format
+msgid "Invalid user id %s"
+msgstr ""
+
+#: admin/users.php:105
+msgid "Uid must be numeric."
+msgstr ""
+
+#: admin/users.php:108 admin/users.php:115
+msgid "Password must be at least 8 characters long."
+msgstr ""
+
+#: admin/users.php:112
+msgid ""
+"Username must be at least 2 characters long and must contain letters and "
+"digits only."
+msgstr ""
+
+#: admin/users.php:125
+msgid ""
+"Groups must be a list of group names separated by commas. Group names must "
+"consist of letters and digits."
+msgstr ""
diff --git a/po/pot.sed b/po/pot.sed
new file mode 100644
index 0000000..96d5728
--- /dev/null
+++ b/po/pot.sed
@@ -0,0 +1,30 @@
+# Copyright (c) 2007 Jan Dittberner. $Revision$
+#
+# inspired by Alex Tingle's pot.sed from
+# http://blogs.admissions.buffalo.edu/news/wp-content/plugins/eventcalendar3/gettext/pot.sed
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+# 
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+# 
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
+
+
+# Fills in some details in the ec3.pot file.   
+1,/^$/ {
+  s/SOME DESCRIPTIVE TITLE/DAVAdmin/
+  s/YEAR THE PACKAGE.S COPYRIGHT HOLDER/2007, Jan Dittberner/
+  s/PACKAGE/davadmin/
+  s/FIRST AUTHOR <EMAIL@ADDRESS>, YEAR./Jan Dittberner <jan AT dittberner.info>, 2007./
+  s/VERSION/0.2/
+  s/CHARSET/UTF-8/
+}
+