--- a/doc/installation.txt	Sat May 06 17:21:34 2006 +0000
+++ b/doc/installation.txt	Sat May 06 17:41:24 2006 +0000
@@ -52,6 +52,11 @@
 
 You may optionally install and use:
 
+Timezone Definitions
+  Full timezone support requires pytz_ module which brings the
+  `Olson tz database`_ into Python.  If pytz_ is not installed,
+  timezones may be specified as numeric hour offsets only.
+
 An RDBMS
   Sqlite, MySQL and Postgresql are all supported by Roundup and will be
   used if available. One of these is recommended if you are anticipating a
@@ -71,6 +76,8 @@
   successfully.
 
 .. _Xapian: http://www.xapian.org/
+.. _pytz: http://pytz.sourceforge.net/
+.. _Olson tz database: http://www.twinsun.com/tz/tz-link.htm
 
 
 Getting Roundup