An Apple iPod or iPhone is an essential travel accessory in its own right. Not only can you listen to music and watch videos, but you can also store your business contacts on either device or use your iPod to back up files.

But as feature-packed as Apple's devices are, you'll probably still want to accessorize them. Here's a look at some cool add-ons for the airplane, car, hotel room--or anywhere you travel.

Getting Power on the Plane

The Inflight Power Recharger ($35 to $50), about the size of a small tape measure, converts the audio output from an airplane's passenger seat headphone jack into power that can recharge your iPod, iPhone, RIM BlackBerry, and any other handheld devices that support USB connections.

Here's how it works: At your airplane seat, find a music channel with up-tempo tunes; turn the volume all the way up; plug your gadget into the recharger and the recharger into the airplane seat audio output jack. You don't have to be in an airline seat to use the recharger, however. With two AAA batteries the Inflight Power Recharger can juice up your device without an airplane audio jack.

I tested the Inflight Power Recharger with my video iPod on two recent cross-country flights. The device extended my iPod's playback time by about 30 minutes--but it took nearly 2 hours to get that charge. And it was awkward to have my iPod and the recharger in my lap, dangling from the airplane seat audio jack.

The iGo powerXtender ($16) is another option for gadget recharging in transit. The portable device uses two AA batteries to recharge iPods, iPhones, and other gadgets, wherever you may be. But you've got to buy a tip to connect a device to the recharger, and a tip that fits iPods and iPhones costs $13. Plus, they're relatively small and easy to lose. However, with so many available tips, it's likely there's one that fits your small gadget.

In the Car

The iPod is among the technological advancements that rendered the car cassette tape player obsolete. And yet one of the easiest ways to play iPod music in the car is through a cassette tape adapter. Ironic, huh?

If your car stereo doesn't have a cassette deck or an iPod hookup, you can wirelessly transmit music from your music player to unused FM frequencies on your car radio.

For example, Griffin Technology's iTrip Auto is a sleek, black device that works with iPods and iPhones to wirelessly transmit tunes via FM frequencies. It's easy to change frequencies using the device's LCD. And because it connects to your in-car power port, the iTrip Auto also charges your gadget while beaming your tunes (not all transmitters do this). It can be frustrating to find a clear, unused FM frequency without static in urban areas, however. At $70, the iTrip Auto is pricey, but I've seen it online for under $50.

In the Hotel Room

The iHome2Go ($99), available in black or white, is a portable iPod stereo/recharging dock/alarm clock for use in hotels, at home, or at the office. The device has been available since last year but was recently given a more streamlined look. It's attractive, easy to use, runs off four AA batteries or AC power, and has a backup battery so you don't have to reset the time when you unplug it or lose battery power.

The iHome2Go produces good sound, though it's no match for sound systems from Bose and other high-end iPod speakers, and it comes with a small remote control. But the iHome2Go weighs about 2.08 pounds with the AC adapter. And when folded flat for travel, it measures 10.25 inches by 7 inches by 1.8 inches. In other words, it's not the most portable iPod alarm clock/speaker system around. The i.Sound Time Travel ($60) is much more compact, for instance (I haven't tested this product, however.) Also, the portable iHome2Go lacks the AM/FM radio of its desktop sibling (also $99).

The iHome2Go works with the iPhone as well. However, you should put your iPhone in Airplane Mode, to prevent interference between the phone and the speakers.

Further Information

1. The Ultimate iPod Accessory--a New York Hotel Room?
2. "Control Your iPod--With Your Mouth?"
3. "Charge Six Devices With One Charger"
4. "Hot iPod Add-Ons"

Mobile Computing News, Reviews, & Tips

An iPod Around Your Neck: A new iPod accessory lets you wear the media player on the back of your neck. NekFIT ($34) is designed for active users who dislike tangled, dangling earbud wires.

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Contributing Editor James A. Martin offers tools, tips, and product recommendations to help you make the most of computing on the go. Martin is also author of the Traveler 2.0 blog. Sign up to have the Mobile Computing Newsletter e-mailed to you each week.