The array of applications, or "apps," available for the iPhone and iPod Touch is dizzying—numbering more than 50,000. Here are our top picks for travelers.
Get packing: Build a packing list with Packing Pro ($4), using an exhaustive database of items. Choose between pre-made templates or start a custom list of your own.
Know the airport: Check FlightTrack ($5) for real-time FAA flight itinerary updates, delays, and cancellations. Use Gate Maps ($1) to view layouts of more than 30 major airports. If you miss your flight altogether, Next Flight ($3) will give you a list of alternate options. And if you need to book a flight at the last minute, Airfare ($4) will query over 500 different airlines to find the best available deals.
Avoid road congestion: Maps (free) can be enabled to "show traffic," and highways will turn green, yellow, or red depending on traffic.
Find a gas station: Cheap Gas! (free) gives you a list of nearby stations plus the fuel prices.
Skirt speed traps: Consult Trapster (free) to identify speed cameras and known speed trap zones along your route.
Make a pit stop: Rest Area ($1) will give you a list of highway rest stops organized by proximity to your current location. If language is an issue, download the Toilet (free) app, and the words "Where is the nearest restroom?" are displayed on the screen in one of ten languages.
Eat local: Urbanspoon (free) queries its database to offer nearby dining options.
Leave a tip: With Big Tipper ($2), just enter the check total, desired tip percentage, and number of people paying to calculate what you should pay.
Calculate currencies: Currency (free) converts between more than 90 different currencies.
Identify wildlife: Try the North Woods Field Guide ($5) to identify trees, wildflowers, insects, and animal tracks.
Send a postcard: Send updates to friends back home using TripTrack ($3). Journal updates and snapshots taken with the iPhone are posted on a website. Prefer an old-fashioned postcard? For $1.29, goPostal will print a postcard using your photo and message and drop it in the mail.