iPhone AUX Cable?

[Jobber]

I have an "AUX in" in my car radio, when I had my Touch I used the simple $2-$3 cable found at Wal-Mart and it worked fine. Now that I have switched to an iPhone (I got both the 2G and 3GS), I notice the pin to the cable seems as if it's not big enough for the iPhone. It seems weird to me, since I can use the same headphones on all three devices. What's the deal? Do I need to switch over to an FM transmitter?

Thanks.

 

[Badfoot]

FM Transmitters are a pain. Your standard 3.5mm jack plug lead will work ok, this is all I use.