As with any car audio/video installation, your first step is to disconnect the negative terminal of your car battery to prevent short circuits (disconnect your vehicle's battery). For onnect an iPod to your car stereo, you need: tools and iPod adapters (wired FM modulators, wireless FM modulators or cassette adapters), power adapters and car mounts
Choosing the iPod accessories
Playing the iPod through your car's radio system
The options range from the tried-and-true cassette adapter, which gives you the most basic kind of audio input, to component installations that give you the highest possible sound quality, let you control your iPod through your car radio.
Convenient in-car iPod solutions
If you just want to get a signal from the iPod to your vehicles's radio without any installation, you have 2 options:
1. iPod cassette adapters - Several manufacturers make a cassette adapter (Maxell, Belkin, Sony). A cassette adapter connects to your iPod's headphone output, plays on your car's cassette deck.
2. Wireless FM transmitters - The wireless FM transmitter, like the cassette adapter, plugs into your iPod's headphone output, the transmitter sends a low-powered FM signal to your car radio. Wireless FM transmitter signals are susceptible to static and outside interference, and can vary in strength and quality depending on your location. Usually powered by your car's cigarette lighter (or by "AAA" batteries).
In-car iPod solutions for better sound quality
Running a direct line from the iPod (or iPod mini, iPod U2) into your car's system will give you cleaner sound.
1. Wired FM modulators - The wired FM modulator, like the wireless transmitter, sends a signal that's picked up by your car's receiver, the modulator connects to the iPod via a minijack-to-RCA cable. The difference is that the modulator is wired directly to your car radio's antenna input, so it delivers a much stronger signal for you to tune in, although there can still be interference from surrounding stations on the dial.
2. Auxiliary input jack - If your car's head unit has an auxiliary input jack, a simple cable connection might be all you need to listen to your iPod in your car. Auxiliary inputs are usually located on the back of a car radio, though certain models offer a convenient front-panel input. For car radios with rear aux inputs, you'll probably have to run a minijack-to-RCA cable from under the dash for the iPod to plug into.
Since auxiliary inputs provide a direct connection from the iPod to the receiver, they give you the cleanest and most detailed possible sound in your car. If your car audio/stereo doesn't have an auxiliary input, there are auxiliary input adapters available for both factory-installed and aftermarket radios that convert the CD changer input into an auxiliary input.
Full-function in-car iPod solutions
With each of the above solutions, you still have to use the iPod's controls to select, play, and pause songs. You also have to look at the iPod's screen to navigate through songs, which can be dangerous while driving.
Interfaces exist, however, which let you use your car stereo to control the music coming from your iPod, and to display the iPod's information on the car radio screen. This can make using your iPod especially convenient in vehicles that have those controls built into the steering wheel - and contribute significantly to safer driving. Plus, these solutions keep your iPod fully charged, so you don't have to worry about running down the batteries.
Brand-name radio iPod adapters - If you've upgraded your car's sound system with a brand-name radio, chances are good that the same manufacturer now has an iPod interface available. These brand-specific adapters connect to a CD changer input, and give you the same superior sound quality as auxiliary input connections. You also get full access to the iPod's menu from your radio and a power supply to keep your iPod charged. Most brand-name radios have superior displays, which makes navigation even easier. Plus you can take full advantage of your system's sophisticated sound-shaping options, so you can get the best possible sound from your iPod's song collection.
Factory stereo iPod adapters - These interfaces are made specifically to connect your iPod to your factory radio. They connect to your factory radio CD changer port and to the iPod, so the sound quality is optimal. They can display the information on your iPod's menu on your factory radio's screen, and allow you to navigate through your iPod's song collection using your factory radio controls, including steering wheel controls. This kind of adapter also charges your iPod automatically, making it ideal for long trips.
Keeping the iPod charged and secure
Keeping your iPod charged while driving, so you don't run out of tunes, is easy. If you're not using an interface that charges your iPod automatically, you can choose from a variety of accessories that let you tap into your car's cigarette lighter for just that purpose. Some are simple, stand-alone chargers, while others incorporate the lighter's power source to run an FM modulator, or power an in-line remote.
While driving, it's a good idea to have your iPod secured in some fashion. A flying iPod after a sudden stop can be a safety hazard - and perhaps a tragic end for your player! If you have a cupholder, you can get a dock that fits inside it. The dock holds the iPod securely, and angles it for easier use. You can also get a combination dock and charger, which uses the cigarette lighter plug as the base for the dock...