Sprint Nextel Corp. rolled out its new 4G phone today, marking an advance that could usher in devices with high-definition video capabilities and faster download speeds, Bloomberg reported.

The Overland Park, Kan.-based telecommunications company began selling the Evo smart phone from HTC Corp., which runs on Google Inc.’s Android operating system and uses the so-called fourth-generation wireless network that Sprint co-owns with Clearwire Corp.

“The most important thing about these devices isn’t really the device itself,” said Jim McGregor, chief technology strategist at In-Stat LLC, a Scottsdale, Ariz.-based research firm. “It’s really the applications and the content that you can use on the device.”

Sprint said handsets such as the Evo will be able to download content nearly 10 times faster than devices with third-generation technology, allowing users to make video calls and download movies.

As more 4G devices hit the market, software developers will create programs to capitalize on the increased download speeds, McGregor said.

And though Sprint is the first U.S. carrier to begin offering 4G services, it is not the only company looking to cash in.

Basking Ridge, N.J.-based Verizon Wireless plans to roll out its 4G network this year, and Dallas-based AT&T Inc., the second-largest U.S. wireless company, has said it plans to introduce the service in 2011.

4G “will make connectivity truly ubiquitous,” said Roger Entner, an analyst at Nielsen Co. “It will make that device you have in your hand even more powerful, even more valuable.”