If I had time to do a medium size unpaid project right npow I would create a real time wiki.
Some ajax code to keep pages synchronized both ways with the server (i.e. sending my updates to the server and grabbing your updates from the server) and a real simple wysisig in browser editing environment.
I'll be looking for it over the next few months and will post a link when I see it. In the meantime there's just
moonedit
Dated: 05/11/2007