from: http://www.engadget.com/2011/08/31/cnbc-facebook-to-launch-music-service-on-september-22/:

The title is all we know for now, but CNBC is now confidently reports that Facebook is preparing to launch a music service in some way on September 22, which aligns perfectly with the conference of the F8 developer company. This service may also include a panel of Spotify ? Perhaps some Vibes ? We will be there to find out.