This instructable will show you who to build a rgb lighting system with an arduino. You can also control it with an ipod/iphone/ipad using touchOSC. In my previous instructable I showed how to control one rgb led in this you can control heaps with a single chip the ULN2003A.
ULN2003A ic or equivilent
common cathode RGB LED's(- + - -)
breadboard or perfboard
Resistors based on your led(I used one per channel)
Cable for linking RGB LED's around your home(optional)