iKross 3.5mm LED FM Talk / Transmitter with Auto-Scan Car Kit for Apple iPhone 3G, 3GS, iPhone 4 4S / 4G 4GS 4th Generation Apple iPad 1 1st Generation iPad 2 2nd Generation and The New iPad Wifi / 3G / 4G LTE Model 16GB, 32GB, 64GB
This did not work on my iphone 3gs; nothing but static.  My son plugged his ipod classic in and it worked fine.  Also, FYI it plugs into the headphone jack and does not charge your iphone or ipod.