Just came across this website http://www.musicmagpie.co.uk/sellit.asp
It's a good way of getting rid of old music CD's that you no longer want. You type in the barcode and they tell you how much the CD is worth. You send them the CD, they send you a check and you've got a little more storage room.
Excellent for anyone who doesn't want to take the ebay or car boot sale route. Also, if you use ipoints, you can get points for doing this.