Morpheus is a decentralized Napster clone that works better than Napster itself. It is based on the FastTrack P2P engine. Gnutella, the other major fully distributed network, is quite slow because every node acts as a server and ends up proxying many requests. FastTrack uses SuperNodes to handle the “central server” function. Also very cool is that FastTrack will download from multiple peers simultaneously for added speed.
A nice overview of the technology shows the flow.