Jamendo
Jamendo is a site on which artists can give their music away to audiences for free, under a Creative Commons licence (which can, of course, include prohibitions against people using that music in a commercial context elsewhere). Fans can make a donation if they wish, but there is no requirement to do so.
Fans get free music via mp3 download, or complete albums via BitTorrent or eMule — and artists get access to a whole community of people that might otherwise never have found them.
Do you need help giving your music away for free? Is Jamendo a solution looking for a problem? How is this useful to you? As usual, let’s have your review of this site in the comments.