Amazon has opened a DRM free music store and by all accounts it's pretty good and 38¢ cheaper than iTunes Plus. But as per usual it's staying below the 49th parallel for the time being.
A different take on the DRM free music service is Grooveshark. It's a peer to peer network (like Kazza) but you pay for songs (and a guarantied level of quality and service, unlike some of the crap you can find on p2p networks) and are paid for songs you share with other users.
I've currently been trying out the beta (of which I have invites) and it seems to work very well in the short time I've been using it. It's just unfortunate that I can't seem to enter my credit card to buy any music.
CNet's Buzz Out Loud podcast interviewed Grooveshark's CEO Sam Tarantino and it was quite interesting to hear.