Announced back in August, development on RIM’s BBM Music service has been moving forward, with regular releases to testers in RIM’s BlackBerry Beta Zone. Today, things are finally ready to go official, and the BBM Music app is dropping its beta status and finding a home in the App World proper.

If you haven’t been keeping on top of BBM Music, its method of operation may seem a bit strange; it’s certainly unlike the other smartphone-based music platforms out there now. From RIM’s catalog of music, you select fifty songs you’d like access to. You can then listen to any of those tracks, and each month you’ll have the opportunity to swap-out up to 25 of those tracks for others of your choosing. That’s admittedly not a lot of music, but RIM lets you augment those 50 tracks with a little social networking. Besides your own tracks, you can listen to the 50 songs selected by your BBM friends who are also BBM Music users.

It’s an interesting take on how to run a music service, and we can certainly see how the ability to quickly grow the library of songs you have access to by adding some more friends will appeal to some users, but there’s something that just doesn’t sit right about a subscription service where some users are getting more for their money than others.

As for those subscriptions, you can use a free account, which isn’t very useful as you can only listen to 30-second clips, or pay for a premium one. For about five dollars a month, you’ll get access to the full BBM Music service. To start things off, RIM is offering a free premium trial – either one month or two months free, depending on your country.

Users in the US, Canada, and Australia should be able to access BBM Music through the App World, starting sometime today.