Frostwire: Limewire’s open source cousin
Limewire is one of the most popular Peer to Peer file sharing applications around, and it's easy to see why. With its simple but powerful interface, it's the next best thing to old school Napster. One thing that cheapskates and teenagers don't like about it, however, is its tendency to nag the user to upgrade to Limewire Pro for a fee.