activeCollab is an easy to use, web based, open source collaboration and project management tool. Set up an environment where you, your team and your clients can collaborate on active projects using a set of simple, functional tools. 100% free.
I’ve been using activeCollab for a month or so and it is the most adaptable, easy-to-use project management application I’ve ever used. Unfortunately the developer is closing up the source as of v1.0, but 0.71 is still open source and hopefully some developers will take that code and begin a new branch of activeCollab.
There is a close-knit active community that is hacking the 0.71 code to add functionality but it hasn’t taken off like I’d hoped.