http://www.installer.com/item/displa....php?it=spi336
With this cable,it connects to the Ipod headphone jack,then splits into 2 RCA inputs that connect to your amp input.You will have to plug the Ipod into your charger too for long trips though.The sound output from the Ipod is not that great,as far as voltage is concerned.Better head units put out 4 volts to get the signal to the amp,but if you're not an Audiophile,it will do.You will just have to crank the gain on your amp up.
http://www.crutchfield.com/s_113KDCX...FBrand|Kenwood
This is the route I took on my '70 GTO project...$140 and you get direct Ipod control,remote...so you could put it in the glove box,etc.,and it has 6 Hi-end 4 volt preamp outputs...and a 2 Year Warranty!!
http://www.amazon.com/Polk-Audio-Pa1.../dp/B0016LY6MA
This is the amp I got...It will run all the speakers,including subs with out the clutter of extra wiring.