Unlimited users can register and participate in your 'public' projects, including posting to your project forums, trackers, and docs. Up to 15 of your total registered users can become full project members.

GForge Advanced Server is available as a free, binary download. Choose either a completely-installed vmware image or an installer that will run easily on Fedora, Red Hat Enterprise Linux 4-5, Debian Etch, Ubuntu 6, or CentOS 4-5 

The vmware image is approximately 485MB and includes a complete installation on CentOS 5. This image can be easily run on any platform that can run recent versions of VMWare Server, Player, or Workstation.

http://gforgegroup.com