Annoying box with song information in top right of screen

Since this afternoon my last.fm scrobbler (Mac OSX) has been putting an info box in the top right hand of my screen with the song name, artist name etc, every time the song changes on my iTunes.

This is the most annoying thing ever, but I don't know how to turn it off. If anyone can help me I'd be very grateful, otherwise it's bye bye last.fm for me, I can't deal with that happening every 4 minutes when I'm working (sounds petty but the little things matter)

Thanks :)