Trac is a Python based wonderful tool which integrates Ticketing, Wiki and Subversion together. Unfortunately the default plugins are not readily available for our day to day needs, for example a scheduler emailing, email integration etc. I have been using Trac now a days very frequently, for which I have wrote a scheduler email module in java.
This is available as a web application, which can be deployed to Tomcat, JBoss or any other java web application servers.
I will be writing one more post to tell you how to configure this. Now here is the link.
http://sourceforge.net/projects/email4trac/