AT&T Inc. today will officially launch an upgraded wireless high-speed Internet service on O'ahu.

The phone company joins SprintNextel and Verizon Wireless, which already offer so-called third-generation, or 3G wireless technology. The technology serves as a platform for advance wireless services including faster data speeds and video telephony, games and music.

SprintNextel launched its Hawai'i 3G service in April. That followed Verizon Wireless' Hawai'i launch last November. T-Mobile has said it plans to launch its own 3G service in Hawai'i sometime next year.

For AT&T, the new technology provides O'ahu customers access to a new service called Video Share, which allows one-way, live streaming of video during a two-way phone conversation. The service costs a minimum $4.99 a month for 25 minutes of Video Share usage.

Download speeds for AT&T's new service ranges from 600 kilobits per second to 1.4 megabits per second, depending on the location of the user. That's five times faster than the company's previous wireless data service, said Edward Maruyama, AT&T's Hawai'i managing director.

The prices for AT&T's data services ranges from $29.99 a month to $99.99 for unlimited service. That's on top of charges for a voice service.

The new service is targeted at customers needing mobile broadband Internet access, and is not meant as a replacement for residential broadband service.

"The benefits and features of our 3G network are a (perfect) match for the outdoor and active lifestyles in Hawai'i," Maruyama said.

AT&T said it spent $49 million on Hawai'i network upgrades during the past three years, which helped make today's launch possible.

AT&T also partnered with Japan's NTT DoCoMo Inc., which pledged to invest up to $24 million on the project. The upgrades allow DoCoMo customers to use their phones while visiting O'ahu.

AT&T's new 3G network is only available locally on O'ahu, however, the company plans to offer the service on the Neighbor Islands next year.

Reach Sean Hao at shao@honoluluadvertiser.com.