If you're a frequent Webware, reader you might remember Grooveshark, and Grooveshark Lite--two different but equally awesome music-sharing and listening tools. From those same folks comes TinySong, a bit of a play on large link sharing services like TinyURL. However, instead of sharing Web sites with your friends, you're linking them straight to the track.
The service uses the same built-in song search found in Grooveshark Lite, and will simply jump whoever opens the link right to the Web based jukebox. What's nice is whoever is searching will have the short link copied to their clipboard automatically. For popular songs there's also a fairly good diversity of variations and remixes.
One thing missing from TinySong is a way to make multi-song playlists, but you can simply use Grooveshark Lite and share the playlist link with a friend. See also services like MuxTape and Mixwit for such a task.