Trac is an open source, web-based project management and bug-tracking tool. We’re using it on pretty much every project in the company. I like it very much for its simplicity and all-sufficiency at the same moment. It has all you need for effective project management based on agile process:

• Wiki – work on the content, attach files, share with other people
• Timeline, which shows all events like check-ins, additions/modifications of tickets, wiki edits, milestone changes
• Roadmap – where are we right now? How much more efforts do we need to undertake to get the project done?
• Browse Source – svn repository browser: compare revisions, see what’s changed. Say «no» to cvs, finally
• Tickets – create, view bugs, tasks, projects, add comments (every ticket has a small forum attached to it – the feature that I love). All discussions can be sent to email, which is very cool!
• Search (well, that’s not even a feature, it’s a MUST for a system of this kind)
• Admin module – where you can add milestones, change user permissions, define components, versions, etc. Everything is very straightforward

You may think that an app like that would be another monstrous bureaucratic system. Try using it and you’ll be amazed by how minimalistic and convenient it is. It became so essential for me that I use it on every project from now on. The only thing that I don’t really like is that it’s written in Python. To me this is something that should have been done in PHP. But hey, I haven’t tried Python yet, so these are the words of PHP freak.