Hook up iPod in 2006 MItsubishi Endeavor?

I have a 2006 MItsubishi Endeavor Limited with the Infinity audio system and have been trying to figure out if there's any way to hook up an iPod to it. I have an FM transmitter but I want something that plugs directly into the system. It really doesn't matter to me whether it's by way of an iPod cable, aux cable, new head unit, or any other ways. Is this possible?