Next time you're traveling abroad, don't forget to pack your world phone. Here's how this little-known technology works and which models to buy.
As I watched the sun set over Barcelona, my phone rang. It was a critical call, from a potential client I'd been trying to reach for weeks. I arranged a meeting upon my return, then quickly called home to check up on my cat. Business and loved ones taken care of, I turned off the phone and enjoyed a stress-free smorgasbord of tapas.

A cell phone can save you when your car breaks down or let you tuck in the kids from another state. But most U.S. cell phones don't work abroad. That's why frequent international travelers should consider investing in a world phone, or global phone, a special unit that works in the United States and in as many as 100 other countries.

Of the major U.S. carriers, T-Mobile (formerly Voice-stream), Cingular, AT&T, and Nextel offer phones that work at home and globally, and making and receiving calls with these plans is easy. After you call your provider to turn on the "international roaming" option, you'll keep your U.S. phone number wherever you roam.
World phones usually cost a bit more than domestic-only phones, but otherwise they have the usual features and options. Just be aware that world phones don't work absolutely everywhere, and that some phones are easier to use than others. All of the phones we recommend below switch between U.S. and world bands without work on your part.

Major areas where most world phones don't work are Japan, Korea, much of the rural U.S. (with one exception; see "Do You Need a World Phone?" on page 66), and parts of Mexico and the Caribbean (although Sprint, T-Mobile, and Nextel phones work in parts of Mexico and/or the Caribbean). Almost all U.S. phones, including world phones, work in Canada.