The poor man's way to play iPod audio, video, and still images through your home theater is to buy an inexpensive cable that plugs into the headphone jack of your iPod and hook it up to the inputs on your TV and home stereo. But if you're looking for a more advanced A/V connection that includes an S-Video plug, a built-in iPod charger, and remote control operation, you need to step up to the Apple iPod AV Connection Kit ($99) or a third-party alternative, such as the Belkin TuneCommand AV reviewed here. The Belkin's list price is $90, but it's widely available online for around $70--if not less.
The TuneCommand AV works with 4G, Photo, Nano, and Mini iPods for audio and photos, but to display video, you'll obviously need a video-enabled iPod--either the original 5G version or the recent upgrade. The TuneCommand AV package includes an iPod dock base station, an A/V cable (three feet long), and a small wireless (RF) remote control. You also get four interchangeable trays to snugly fit various types of iPods in the dock, as well as a lanyard and a belt clip so you can wear your remote around the house, if you're the type that does that sort of thing.
As far as connectivity goes, you have several choices. The simplest option is to attach the included A/V cable to the variable volume A/V output on the back of the dock. One side of the cable--the side that plugs into the dock--looks like your standard headphone jack, while the other side looks like your standard red, white, and yellow composite audio/video jacks. The advantage to this setup is that you can control the volume using Belkin's little white remote, which controls your iPod from as far away as 120 feet. The downside is that you're not getting the best video connection; for that, you'll need to provide your own S-Video cable.
For the majority of our tests, we connected the TuneCommand AV to a TV with an S-Video cable and opted for the fixed stereo line-out route using standard red-and-white RCA audio cables (also not included). This afforded us the best picture quality, but we did have to control the volume with the TV's remote (if you connect the audio to your A/V receiver's inputs, you'd use the A/V receiver's remote to adjust the volume).