It seems that Microsoft have expanded their Music Streaming service away from the XBOX 360, with the app now available for any android device and also any iDevice running at least iOS 6. Sources report that streaming music via the internet is entirely free for the first six months, however afterwards you'll require a paid Xbox Music Pass subscription to take advantage of the service.
XBOX's music streaming service functions like Spotify, Rdio, Google Play Music: All Access, and Apple iTunes Radio. It simply let's you listen to music on demand and also create set playlists to enjoy your songs at a later date. At the moment, the new iOS and Android apps do not currently let you save and play tracks offline, although that functionality is expected to arrive "in the coming months."
You can download the app right now from iTunes and also the Google play store. An 'XBOX Music Pass' will set you back a modest $9.99 a month or you can buy a year pass for $99. They also offer a 30 day free-trial if you wish to try it before you purchase a subscription.