Last.fm is a highly recommended app for any music enthusiast. It is basically a music recommendation engine. It works by taking the data from the songs you listen to and recommending similar artist/bands. Now this isn't something new with what they are doing, but the way Last.fm is going about it is what makes it revolutionary. Last.fm is now including their software in other applications. So for example when a user plugs their iPod up to their computer it will "scrobble" their songs to the Last.fm server and uses they dating in a "social networking sense" to give out its recommendations. If you are looking to find new music/songs/artists/bands this is the best route to go.