I'm actually trying to build exactly that ... http://www.fluidplay.com. It is like media master, but it is streaming from a local PC instead of uploading your library.
oh ok. Well the model will be cool if an user can stream songs for others to listen. Say buy rights for the song and if someone has to listen to same, he can request trade or buy the song for airing it. This way he or she recovers money and could be something worth. rather than paying 99 cents and owning it and listening for few days...one can trade it and find ways to earn back 10 times :D