Many newer car stereo's are have connections that allow MP3 players like iPod to be hooked up and played through the stereo. For new car stereos, you only need to connect your device and select the MP3 player option. If you have an older stereo, you will have to connect your iPod either with a 3.5mm stereo jack cable or a FM transmitter. Connecting the iPod directly to the stereo with a stereo jack cable will result in the best sound quality versus the FM transmitter which can suffer from static or signal interruption.
Locate an AUX port. The AUX is a single, small hole that will be located on your car stereo face. (It is sized perfectly to plug in a set of headphones or an AUX cable.)
Plug in your 3.5mm stereo cable into the hole on the front of your car stereo.
Insert the other end of your stereo cable into the AUX/headphone jack hole on the top of your iPod.
Turn your iPod on.
Enable the AUX input. This will be different for every car stereo. You may need to field through your input options (e.g. FM, AM, CD, etc.) in order to access the AUX. Or you may need to hit your stereo's Menu button. Then field through the additional input options in order to enable the AUX input.
Locate a song on your iPod and hit the Play button once the AUX input is enabled. If you don't hear anything, make sure the volume is turned up on the iPod device as well as the car stereo. If the iPod is playing your song, you will see the song progressing on the iPod screen.
Find a FM transmitter that is compatible with your iPod. Then arrange your FM transmitter near your car stereo.
Connect the iPod to the FM transmitter. (Refer to your transmitter's user guide for specific connection instructions.)
Tune the radio on your car stereo to a frequency that has nothing but static, then tune your transmitter to the same frequency by using the + and - buttons.
Power on your iPod. Then find a song and hit "Play." Make sure to turn your volume all the way up on your iPod. You should be able to hear your song. If not, locate a new frequency until you find one that works well with your transmitter and iPod.
Some FM transmitter's like iTrip require that you install software on your computer then load it unto your iPod. Then navigate to iTrip on your iPod device. After that you would select the station your iTrip should tune to.