I just wanted to lend my support to this idea. Let me know if you need additional software installed, configured, etc. I'm also happy to promote this in all my available channels (UT, Astronomy Cast, etc).
Perhaps a Wiki might be a good format to do this? Maybe something similar to the Wikibooks.
http://en.wikibooks.org/wiki/Astronomy
There are a lot of unwritten sections in their book which we could complete, since it's open for editing by anyone. We could then integrate the wikibook entries back into this forum as part of the course. That would probably take a lot of hassle off everyone's hands, and encourage other people to contribute.