We love the word 'free', especially when it is applied to a previously premium product. Like BBM Music for example.BBM Music for the BlackBerry launched in the UK just last month, but at a cost of £4.99 per month. However, RIM, obviously keen on some Christmas sign-ups, is now offering the service for free on these shores. Download the app before 4 January 2012 and you get six months of BBM Music for nothing. If you have already signed up and started paying, don't worry, you've not been forgotten about. You get four months of free BBM.There doesn't seem to be any catch. RIM presumably believes you'll love the service so much that you will want to pay the £4.99 when the promotion ends. You might well do too – BBM Music is part music service, part social network, that latter part perhaps being key to you hanging around when the money is due.Sign up and you get access to 50 songs each month. But if your friends use the service, you get access to their 50 tunes too, as well as being able to create playlists with both your tunes and those of your friends. So the more you hassle your friends to sign up too, the more music you have. You can also 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.If that appeals, go get the app now – or before 4 January – if you want the freebie.