The soundtrack of FLCL is made up of songs by a band named The Pillows. All of the songs on the soundtracks come from their older CDs. The official soundtrack is made up of 2 CDs, Addict and Kaizoku-Ou (Pirate King). Unfortunately, these CDs do not have all the songs that were in the series and are the edited versions (meaning the lyrics were taken out/edited for many of the songs).
What makes the soundtrack so cool is that it is mostly done by one band to give the entire series a certain feel, and all the music fits into the scenes so well. This series has turned many people on to The Pillows' music, including me.
A fanlisting is "a place for all fans of a particular show, movie, actor, actress, singer, etc. to come together and build the biggest listing of people from all around the world who are fans of that subject." If you're a fan of the Music of FLCL, please join!