I've been having fun lately with free music on Amazon's cloud. They've got a free Cloud Drive where you can store 5GB of data. They also offer a free Cloud Player that allows you to play music that you store on that Cloud. I've been testing it out with some of the 'free' music on Amazon. I keep it on the Cloud and then download it to my PC for transfer to my MP3 player. It actually works pretty well.
Web Service Review: Amazon Cloud Drive and Cloud Player