Spotify - Map shows when two people play same song at same time
Skip Tunes - Control iTunes, Spotify, or Rdio from your Mac's menubar
eSound - Your music. Without limits.
Baritone - Spotify controls that live in your menubar.
Jango - Jango internet radio is all about making online music free, easy and fun.
Muzzy - it’s a tiny and gorgeous iTunes companion that lives on your menu bar. For Mac OSX, its free!