2004 land rover discovery hook up

I was wondering if anyone knew if there was an ipod connector which connected directly to the rear of the Alpine 6 disc changer. Ive seen several ebay auctions for Alpine mp3 cd changers with a direct ipod hook up. So i figured maybe someone knew of an ipod hook up for the stock changer so i didnt have to change my cd changer. Or if anyone knows how to hook up an ipod in the easiest / simplest / cheapest way to hook up an ipod to the 2004 land rover discovery.

thanks
alex