Cell Phones as Net Phones: Worth the Hassle?

Free Overseas Calls

You don't have to use Rebtel with a cell phone, but because cell phones let you dial stored numbers at the touch of a button, they are the easiest way to use the $1-a-week service. Once you've set up your account on Rebtel's Web site, you enter the number you wish to call, and the site generates local numbers for both you and your overseas friend. You then dial the local number for your friend, and the overseas number rings. To make the call free, the recipient must hang up within 30 seconds of answering and then call you back on the local number Rebtel generated for you. You stay on the line, and when the other person calls back, you're connected and chatting for free.

In our tests with numbers in the United Kingdom and Germany, Rebtel worked as advertised, with one glitch: The number it generated for our friend in the UK was not a local call for her. Rebtel can't generate local numbers for all areas in the countries it serves, so the call might not be free for the recipient. Voice quality for all Rebtel calls was on a par with that of U.S. cell phone calls.

Industry experts say these services may not appeal to everyone. "The cost of international calls and roaming calls could be greatly reduced," says Rob Fortino, a director with research firm Telephia. "But you have to balance it: The mobile VoIP provider may charge you a fee, and then there's the per-minute charge on your cell phone. Still, anyone who makes a lot of high-cost calls with their cell phone would want to look at this."

Analysts also agree that the playing field may change dramatically when handsets and services that can seamlessly switch from cellular to Wi-Fi networks become more widely available. (T-Mobile has announced plans for such a service, but it is available in only a few areas so far.) Such a service might shift your cellular call to an available Wi-Fi network to cut your costs.

If you use your cell phone primarily to make in-network domestic calls and your plan allows for unlimited U.S. calls, you probably wouldn't benefit from these VoIP services. But if you make a lot of international calls, these services could be a real deal--if you're willing to put in the time and effort they require.