I managed to completely screw up the tags system for the forum when I played around with the preview 1.2.8 version of the app engine sdk. I wanted to test how the multiple tag association and searching would work with the "IN" keyword, it looks neat and tidy from a code stand point but is very inefficient with the writes. If I cache heavily enough than we should get away with it however. I have finally figured out what I broke though when I reverted back to a non multiple tag version of the forum, so the forum is usable again.
I have decided to use Google Wave as the main source of communication and collaboration for the project. I will be working on writing up some guides to make it easy for people to jump in and help with the forum development when I am not busy coding the forum. I want to make the forum look a little more like the designs, then I will upload the forum to the app engine servers for people to play with. It will be very far from complete though, so you should only check it out if you are curious to see what has done as it won't give you any indication of what the finaly product will look like. Expect that to happen soon.
I found a very nice site that provides free svn and git hosting that I am using for the flow forum source control. If you have a need for such a thing for your own project you should check out unfuddle, there site is very slick and has performed flawlessly for me so far.