The manual says it has a cd changer port. the radio is made by blaupunkt. you can get a blaupunkt ipod cable. I looked into it before but still havn't gotten around to doing it. Got this email but never called the number:
"For information on using the Blaupunkt iPod cable to connect your iPod video to your Opel factory-fitted radio, contact the Blaupunkt technical helpline on 01895 838 880. They will be pleased to assist you.
The iPod adaptor is in stock for immediate dispatch.
If you have found another solution please let me know.