The cables you purchase through Jensen directly for about 20-30 bucks depending on which one you need. Check your manual for cable options or online lists them too. Also note if you your generation of Iphone, pod are compatible with your unit. With this cable it will interface, charge and work in sync. Otherwise you will go through the headphone jack as advised above but not charge while using it unless you have a 12v source and charger to plug into it close by.
There is a black female plug in the rear of the deck that you need to plug this into for it to work. It's labeled as Ipod cable.