T-Mobile will be the first carrier to offer a mobile phone powered by Google’s Android software, according to people briefed on the company’s plans. The phone will be made by HTC, one of the largest makers of mobile phones in the world, and is expected to go on sale in the United States before Christmas, perhaps as early as October.

The high-end phone is expected to match many of the capabilities of Apple’s iPhone and other so-called smartphones that run software from Palm, Research in Motion, Microsoft and Nokia to access the Internet and perform computerlike functions.

The HTC phone, which many gadget sites are calling the “dream,” will have a touch screen, like the iPhone. But the screen also slides out to expose a full five-row keyboard. A video of the phone has been posted recently on YouTube. A person who has seen the HTC device said it matched the one in the video.

The phone’s release date depends on how soon the Federal Communications Commission certifies that the Google software and the HTC phone meet network standards. Executives at all three companies are hoping to announce the phone in September because they would benefit from holiday season sales. The people briefed on the discussions declined to be named because they were not authorized to discuss the project.