Available in the US since August, BBM Music is now available in the UK to the company's eight million users in the UK. If they all take it up, that could be quite a lucrative venture for RIM.If you missed it earlier, it's a mix of music and social networking. Pay the £4.99 monthly fee and toy get access to 50 songs each month. But if your friends use the service, you get access to their 50 tunes too. So the more popular you are, the more music you have. If friends are thin on the ground, you can swap up to 25 tracks at any one time, with all the tracks able to be played either within a network or offline, thanks to offline storage. Should be some decent tracks on offer, with the likes of Universal, Sony, Warner and EMI supporting the launch.Other features too, including the option to create playlists with both your tunes and those of your friends, being able to see any tracks that are new to your circle and being able to check out the most popular tunes amongst your social circle.Does that appeal? Head over to BlackBerry App World to get started.