Currently, Cingular has service in 95 countries and 3G service in 16 metropolitan areas in the United States, which equates to about 52 cities. 3G service rollouts will continue through the remainder of this year, Johnson said.

The phones are backward-compatible with GPRS with a 35Kbps to 40Kbps performance, EDGE with a 70Kbps to 135Kbps performance, and 3G with a real-world performance of 400Kbps to 700Kbps, according to Johnson.

David Hayden, chief wireless analyst at Gramercy Ventures Advisors, said the flat rate plan rather than the tri-band capability is the lynchpin to its success.

"The key is no other carrier is offering a single [worldwide] roaming data plan," Hayden said.

The service also includes software that supports a notebooks-embedded Wi-Fi radio.