In case you don't know, the BBC is pretty happy to take down sites hosting their content. Be careful. I'm pretty sure Mixriot tried the same thing and got burned.
Feedback-wise, you might want to look into more flexible search for non-standard letters. Concrete example, "Tiesto" returns no results, but "Tiësto" returns seven. I have a feeling most people are not going to take the effort to find an umlauted e and will just assume you don't have any of his mixes.
Yep, right now I'm using Soundcloud and following a user on there who frequently posts new sets from popular artists. But it's just one user; I'd love to see that concept expanded upon and taken to a new site entirely. This site has been bookmarked; I'll be tracking to see where this goes!