I wrote a tiny quick and dirty squeezebox controller yesterday.
It sits in your tray, it shows a notification on song changes, and allow you to pause/play/prev/next.
You can get the code here: https://launchpad.net/squeeze-notify
it however does not compile, because a few vala bugs needs to be fixed first. (I seem to hit them constantly).
Q
p.s. I need a nice tray-icon.