Need help hooking up ipod to 99 chev lumina?

i just bought a luxury edition 99 chevy lumina, and i want to hook my ipod into the stereo system. id rather not change the stereo out, as i enjoy the ability to control the stereo from the steering wheel. what sort of adaptor is required for this process? i do not have aux plugs anywhere on the factory (delco) stereo. i read somewhere that you can hook the adaptor into the cd changer input, but im not sure how well this works and would like more info. thanks.