Slashdot just mentioned a NY Times article on file-sharing. In it, the author lists gobs of legal sources for music on the web. The author also mentions that it's not all top quality stuff. But some of the sources, like webjay.org, let users post playlists, meaning it's stuff that they think is good. Find a poster who you share tastes with, and you could be finding good music to download legally and properly.
Which is what we all want, right?