Just sharing some code and source files. You will need the Flash Player 9 to view the example and a decent broadband connection will help as the music file is streaming.
The following demo shows of the new audio capabilities of Flash 9 in particular the computeSpectrum() feature which allows you to drive animations of the audio.
The demo is located here
http://www.dhtmlnirvana.com/flash/spectrum/
and the source files so you can play around with it and come up with your own equalizers are located here. Note it is a 6 meg download.
http://www.dhtmlnirvana.com/flash/spectrum/flash_equalizer.zip
Eddie