If you use Pidgin (the multi-platform, multi-network messaging client) and want to have your currently playing track as your status check out pidgin-musictracker that does just that. Get the files from the website below or if you are on Ubuntu just install it from the repos.
sudo apt-get install pidgin-musictracker
Pidgin: http://www.pidgin.im
pidgin-musictracker: http://code.google.com/p/pidgin-musictracker/