Andrew, and anyone else. I know that Roberto Mello, Ola Hansson, and myself have CVS access. I don't remember if anyone else has worked on it. We don't have any formal process, we have been coordinating mostly in the #openacs IRC channel at irc.freenode.net.
We will have to come up with something a little more strict once the site goes live.
I have been managing the project, so if you want to volunteer, contacting me is best.