Rdio is a very cool social music music service that was previously limited to a select few devices. I stopped using it because it did not support the BlackBerry Torch 9800 since it launched in August. It took them over 3 months but they have now added official support for the BlackBerry Storm, Torch, and Curve 8500 models so more users can try it out.
The app and service cost $9.99/month and let you listen to over seven million songs from your BlackBerry and PC. The service is the brainchild of the founders of Skype and Kazaa. My favorite feature is that you can also sync music to your BlackBerry to listen to offline. The app lets you manage your music collection from your BlackBerry and you can also buy tracks for 99 cents to keep after your subscription. The service and app is currently available in Canada and the US but hopefully will expand further.
You can read more about the service and download their app at www.rdio.com. You get a free trial to test it out before you have to start a subscription.