if you want to do it all yourself then go on crutchfield.com or cardomain.com
if you want someone else to do the work go to circuit city or best buy... but i will warn you ask around and see if you know anyone who has had problems with the install staff at those places... around here the best buy guys do a better job then the circuit city guys... and check there policies on botched jobs.. as a fiend of min got screwed by CC a few years ago after getting a new CD player in his car... when he had the cd player on his wipers would automaticcally turn on and he would have to turn the wipper to on mode to turn them off.. CC told him it wasnt their fault and basiccally told him to go to helll... that was years ago and their policy/ management might have changed