define "sync" with laser? a laser doesnt do anything by itself other than shine. are you talking about in a laser scanner set up? or maybe even a computer controlled spirograph? either way go to the "laser shows" section of the forum.
Or if you only have speakers you can glue a mirror to the speaker and reflect the laser off of the mirror, it will react to the music depending on the vertical travel length (I think it is called Xmax) of the speaker. Bigger with more power is usually better.
Like Chipdouglas said, go over to the laser shows section and look around, theres quite a bit of neat stuff there.