What do FM transmitters do? They send audio wirelessly to your car stereo and broadcasts it to your FM stereo, producing quality sound.

Transmitters Controlled by Your iPod
These simple devices plug into your iPod's headphone output jack. After loading the transmitter software onto your iPod, you can select the broadcast frequency with the iPod interface. A good example of this type of transmitter is Griffin's iTrip.

Universal FM Transmitters
These are standalone devices that can work with any device that has a headphone output jack. This transmitter uses its own batteries, connects to your iPod's headphone jack, and broadcasts audio via a frequency that you select. A good example of this type of transmitter is Belkin's Tunecast II.

All-in-one iPod Car Kits
These contain everything you need to paly your iPod through your car speakers and recharge your iPod at the same time. An example of this is DLO's Transpod FM (which includes a dock, FM transmitter, and car charger).

Advantages

• It's a quick and easy way to way to get sound to your car's speakers
• Cost-effective
• Can be used in any car

Disadvantages

• They are susceptible to interferences, interruptions, and many stations crowd the FM band
• Its effectiveness relies on the quality of your stereo's FM receiver
• May or may not include a charger and you might be limite to the normal playback of your iPod (8-15 hours)