Re: Beginners Questions
Edit// too slow 
Yes WPMU is now defunct; you have WP 3.0 so already have the capability of running it as a MS install, you just have to do a little manual configuration to enable it which is explained over on the WP Codex.
I think a sub domain is the easiest approach, hardest aspect is working existing theme into BP.
Don’t dismiss writing HTML / CSS completely especially from a hand coding point of view, I would say there are a few of us around that would probably express the sentiment that they hoped WP and other cms’s didn’t become the defacto standard for web sites, as much as I like WP
