Driving RGB Leds with Arduino(Audio Input 3.5mm jack, Spectrum Analysed)

Hi, This is my first post, Ive been fascinated with RGB LEDS and syncing them with Audio.

What I really want to build is basically a LED colour Organ, but i want to use RGB LEDS which should be driven by an ARDUINO UNO(Software spectrum analyser).

I could not find how to analyse the Audio spectrum in the Arduino and then drive the LEDS.

For starting off i just want to split the spectrum first and drive a couple of leds according to the frequencies.

It would be appreciated if someone could help out! Thanks!