led + audio?

Hey guys so about a year ago I ran into a guy and we were showing each other are cars. Then he showed me how he had LED lights dancing to the beat of his music in the car. Anyways I think that's something I want to do for my next project and my google searching didn't turn up much useful info so id like your help on completing this project :) any info on parts and things I'll need is what I'm looking to get answers on.

First try connecting LEDs across the speakers. The LED string voltage is designed for the maximum output voltage. For split frequencies or volume independent modulation/arrays you'd be looking at things like "musicolors" or line amplifiers that split frequency bands to different (colored) strings and amplify the signal.