A great site I've been visiting a lot lately is Real World Remixed - a site that releases multitracks of songs (5 so far) and then allows you to upload and listen to remixes of those same songs. Plenty of free streaming tracks there by the bushel, and if you're feeling artistic you can even try your hand at a decent remix of a tune. (The Peter Gabriel hit "Shock the Monkey" stands out from the rest. )

I'm registered there as DJ KroD and have done several renditions -- anyone else here heard of this?