After a week of teasing tweets, the much-anticipated Twitter Music for iPhone and web arrives today, providing a new way to discover music and emerging artists. The app is split into four tabs: Popular, Emerging, Suggested, and Now Playing. The first two tabs suggest music based on tweets from the entire Twitterverse, while the latter two make suggestions based on your own Twitter stream (aka. only the tweets of people you follow). It also highlights artist profiles so you can see which artists they're following and listening to. And of course, you can tweet about a song from within the app.
The service integrates with three mainstream music services to start with. If you subscribe to Rdio or Spotify, you'll be able to listen to full tracks; iTunes users will be only be able to hear the shortened previews you would normally find on iTunes.