SpotiMy - Play/Pause and Next/Previous functions for Spotify directly on your Menu Bar!
Last.fm - The world's largest online music service. Listen online, find out more about your favourite artists, and get music recommendations, only at Last.fm
Muzzy - it’s a tiny and gorgeous iTunes companion that lives on your menu bar. For Mac OSX, its free!
Maloja - Simple self-hosted music scrobble database to create personal listening statistics.
Owlead - Grow your Twitter with valuable followers, effortless
Pandora - Pandora Radio is a free (ad-supported) internet radio founded in 2000.