Cool stuff!
Just wanted to throw in one tip. Coda.fm recently launched and is a very clean and organized music torrent site. Every torrent is verified for no viruses and whatnot, and information is provided a la Last.fm It might be a good idea to try to initiate some sort of partnership (as in, use them for a primary search). Just a thought. They're young and growing, but the cleanliness and functionality remind me of Songbird.
Good idea and I'll see ya at 1.0.