Ya, you need to get an ipod cable that has a USB connector and a standard A/V connection on one end.
Like this one: http://www.pioneer.eu/eur/products/25/38/301/CD-IU230V/specs.html
You plug the usb part of the cable into the usb that comes out of the back of the AVIC and you also need to connect the A/V portion of the cable to the back of the AVIC as well. If you just use the cable that came with your IPOD, all you will be able to do is get the control interface up on the AVIC. Pioneer sells the appropriate cable, but i believe that any standard ipod cable that has the USB & A/V connections will work as well.