This popped into my email today. Looks like a good deal… includes an FM transmitter and appears to be a rod that pokes out through your car charger socket. It's listed as iPhone 4 compatible.
I've bought one, will see how it goes. I hope it doesn't set my car on fire, thankfully I have fire insurance.
I've just bought one as well and gonna to pick it up today. Will see if the sound is clear enought.