Yes, it is possible.
You have 2 ways to do this.
1., Fm modulator. I think this one has poor sound quality.
2., You can connect it through the changer port of the head unit, but then you have to make a switch witch selects Ipod or changer. Like the ones on the forum. If you choose to do this, then you have to emulate the cahnger's communication and you will require an analog-to-SPDIF converter. Like the one I'm worikng on.