If you haven't seen CodePlex, you'll want to check it out. It's Microsoft's shared community development web site, and it uses TFS to host development projects. Brad Wilson of the CodePlex team provides some nice answers to about 10 questions of general interest on TFS and CodePlex.
Phil Haack has some questions about CodePlex and our use of Team Foundation Server that I'd like to answer. Note that I'm not trying to convince Phil to use CodePlex; rather, I want to clarify answers to his questions so that he and others can make the best decisions on their own. (That said, of course we'd love to have SubText on the site. It's an excellent example of a well run and successful open source project.)
For more information on branching and merging (one of the questions), see the post Overview of Branching, Merging, and Shelving.