How to Hook up Your iPod to a Car Stereo

Hooking an iPod into a car stereo is simple. You have three basic options - use RCA cable, go wireless with an FM transmitter, or connect via cassette tape. If you go with an FM transmitter, follow the instructions that come with it. This sometimes involves installing software on your PC, downloading the radio stations to your iPod, finding a station with no feedback at all, and matching the station on your stereo to the station on the iPod.
Steps
1. One of the easiest ways to connect an iPod, if you happen to have a cassette player in your car, is to buy a cassette adapter at your local Radio Shack or Best Buy store. They generally run about $15 dollars, and it's an easy way to have a good quality hookup to your car. You simply plug a standard plug into the earphone jack of your ipod, and a cord runs from that to a cassette which you place into the cassette player. Tune your car stereo to cassette, and you're ready to go (any cassette adapter at those stores should work with the ipod, so don't get suckered into buying the most expensive name brand). It is worth noting that the cassette tape is an analog medium, and therefore suffers no loss in audio quality.
2. Another simple fix is the wireless transmitter; these devices usually attach to your iPod, and require you to tune your radio to a designated FM frequency. While this is certainly the quickest and easiest fix, wireless transmitting has it's drawbacks. First, you will notice a slight decrease in your overall battery life. Second, FM radio transmissions do not usually exceed 96 Kbps, which means that any high-quality audio files (128 Kbps MP3 or higher, AAC, FLAC, MP4, etc...) are down-converted before being transmitted to the radio. This loss in quality is irrelevant to the untrained ear, but intermediate and advanced listeners may notice a drastic difference, especially on high-end stereos.
3. As far as sound quality is concerned, using RCA cables is your best option. Gather your tools.
4. Remove the stereo from your dash. If it's a newer vehicle, you may need a special tool which usually just looks like 2 U's. The pointed ends are inserted into small holes on either side if the stereo. Pull the handles away from each other (pull the left one to the left, and the right one to the right). Pull, and the stereo will slide right out. If you have an older car, you will have to find out how to remove the dash and/or stereo. Sometimes it is just a couple of screws, and the rest is held on with clips. On others, you have to figure it out with trial and error (but remember, the more errors you make, the worse your car will probably look in the end). Ask some friends who may have the same car as you, or look it up online so it's done right.
5. Be sure that your stereo has some type of input in the back. If your stereo has a CD changer input in the rear with RCA inputs, you aren't out of luck - but you may be out another $50 because you need an adapter that changes the CD changer input into simple left and right RCA inputs. If you already have RCA inputs, there will be 2 of them (left and right audio). Usually, one is red, one is white, and they may or may not be covered by small rubber caps (depending on how old it is). If there are caps, you can remove them.
6. Decide where you will be putting your iPod and where you want the wire going. Once you've done this, drill your hole. For a way to make sure the wire never falls through the hole (forcing you to take everything apart to get it), go to step 7. Otherwise, skip to step 8.
7. Cut the RCA wire and splice it. (edit: splice it? splice what? dont splice anything! if its RCA then the RCA to 1/8th inch jack should be fine, get an extension for the 1/8th inch if you need it but dont go splicing wires! also i wouldnt drill any holes i would just find a way to run the cable under the dash, but back to what you were saying...) First, drill your hole where you want the wire to go through, but make it just big enough so the only the wire itself can go through (not the larger end of it). Then, cut the RCA wire and feed it through, making sure that the end that plugs into the iPod (the end with only one plug) is out toward you. Then, behind the dash (or wherever you drilled your hole), splice the wires back together, but be very careful because there are 4 wires you must put back together. Strip the wires very carefully, splice all wires back together, and be sure to tape all exposed metal. Also, about an inch ahead of the splicing, put a bunch of tape (or tie a knot in the wire), so that when you pull the wire, it would stop at the tape instead of at the splice. This avoids the possibility of ripping it apart.
8. Plug the end with the two plugs (white and red) into your stereo, feed the wire where you want it to go, and put the other end through where you want it to come out on the dash (if you haven't done that already).
9. Be sure it works before you put your dash and stereo back together. This usually requires switching to an "input" mode or "auxiliary" mode on your stereo. If it works, you're all set. Replace your stereo and dash.
Tips
1. An easy way to keep your iPod involves a regular cell phone holder, but be sure it is adjustable and it opens wide. An easy way to find these is look for ones that say they can hold your cell phone or a Palm Pilot.
2. There are new Alpine and Pioneer brand product that allow you to plug your iPod into it, then plug it into your aftermarket stereo. It allows you to control your iPod from your stereo, and it also charges it.
Warnings
1. Do not try cutting the RCA and splicing it if you have never spliced any wires before. It involves getting to 4 concealed wires, and it is kind of tricky.
2. Make sure no metal is exposed on the wires when you're done. Exposed metal can contact other metal and cause short circuits, damaging your iPod, car stereo or both.