Geez, I would hope so - since they already have an attachment that allows you to pick up your IPod on your radio...
Those wireless attachments are getting better, but the quality still sucks compared to a direct connection. I've tried a couple in the past that were full of static, and had to be within a couple inches of the car radio in order to get picked up. Last month I bought a $20 gadget called VRFM7, looks like a cigarette lighter, plugs in the car power socket, has 7 fm channels to select from, and has a 10 foot range. Has a mini-plug connection and cable, works decently with my iPod and my other MP3 players. Not only that, it has a USB port for my flashcards and has control buttons (prev, play/pause, next, and volume) for flashcards. Sound quality is decent with no static, and doesn't fade in/out like other wireless gadgets.
But I'd still prefer a direct wired connection to the car stereo system. You can buy aftermarket car stereos from $100 up that have iPod wired connectivity.