Twitter rolls out #Music app for iPhone and web, with iTunes, Spotify and Rdio integration

twitter music appTwitter plans to launch its music discovery app, #Music, Thursday after a few weeks of rumors. The free app, which Twitter announced Thursday morning on ABC’s Good Morning America, will be available starting later today on the web and in Apple’s iTunes (s AAPL) store as an iPhone app. It was built by the team behind We Are Hunted, which Twitter acquired last year.

In a post on its blog, Twitter explained how the app works:

“It uses Twitter activity, including Tweets and engagement, to detect and surface the most popular tracks and emerging artists. It also brings artists’ music-related Twitter activity front and center: go to their profiles to see which music artists they follow and listen to songs by those artists. And, of course, you can tweet songs right from the app.

The songs on Twitter #music currently come from three sources: iTunes, Spotify or Rdio. By default, you will hear previews from iTunes when exploring music in the app. Subscribers to Rdio and Spotify can log in to their accounts to enjoy full tracks that are available in those respective catalogs. We will continue to explore and add other music service providers.”

#Music will be available today in the U.S., Canada, U.K., Australia and New Zealand. Twitter says that “over time” it will expand to Android and to other countries.