You can connect an iPod or iPhone to the factory nav radio and make it think it's a CD changer. It also lets you connect a USB thumb drive to it for the same purpose as well as an auxiliary input such as satellite radio or another portable music player. It's plug and play and you can make up to 5 play lists to control as CDs with 99 tracks and then an additional 6th "CD" that hands over control to the iPod so you can play more than the 495 songs that you can use with the playlist feature. Everything is outlined in the first few posts of this thread. Feel free to ask any other questions you may have.

Take care.