The first case (as far as I’m aware) enforcing a Creative Commons licence has come out in the Netherlands. The case involves famous podcaster Adam Curry, who had a number of pictures in Flickr under an Attribution-NonCommercial-Share Alike licence. Some of the pictures were taken by Weekend, a Dutch tabloid, and placed in the cover. Curry sued over infringement of the non-commercial and attribution elements of the licence, and apparently has obtained €1000.
An interesting case that proves that CC licences are enforceable in court.