Tim: I already have a Google email address,

john.c.baez AAATTT gmail.com

where "AAATTT" stands for that little @ thing.

Please let me know what else I to tell you, or do.

Apparently subversion is so simple that even mathematicians use it (to collaborate on papers written in TeX). Alas, I have not personally reached the point of using version control systems for collaborative math projects. But I'm not opposed to it.