LOS ANGELES -- Microsoft revealed a motion-sensing gadget for the Xbox 360 that it said will change the future of entertainment -- and not just play catch-up with Nintendo's Wii.

If it works as promised, the device could dramatically raise the ante in the competition between the Xbox, Wii and PlayStation and usher in a new era of immersive entertainment.

Code-named Project Natal, the device is a horizontal bar about nine inches wide and stuffed with cameras, depth sensors and array microphones.

(UPDATE: A bunch of new information about the device and future plans for it were disclosed by Microsoft Games Studios boss in this interview)

SOURCE: Microsoft

The prototype controller looks huge in this image supplied by Microsoft but it's not much wider than the Nintendo Wii sensor bar.

It can detect the voices and motions of people nearby, so they can interact with an Xbox and games just by talking and moving their bodies.

Prices and timing weren't available, but it won't be available until 2010 at the earliest and will probably cost around $200. Microsoft has already given game developers tools to start building games that uses the device.

At first it sounds like a challenger to Nintendo's Wii, which uses motion-sensitive controllers. but Natal recognizes gestures and motions made by the entire body without any sort of controller in the hand, Microsoft Vice President Shane Kim said.

"This goes way beyond the Wii," he said.

Natal will also add voice control, so users could walk up to an Xbox and use their voice to start a movie or check messages.

Kim said the device is intended to remove "barriers," making the Xbox more accessible to people who are intimidated by all the buttons and controls on a traditional game controller.

During a rock concertlike production at USC's Galen Center this morning, the company is also unveiling 10 new games and new services for the Xbox 360.

Microsoft's adding Twitter and Facebook to the 360, so users of those social networking services can check and post messages from the console. Adding these services is part of Microsoft's effort to make the Xbox Live network "the next generation social and entertainment network," Kim said.

New details are also coming out about the Zune video store that's replacing the Xbox Live video marketplace. The Zune software will play full 1080p movie rentals instantly, on demand, if users have a fast enough Internet connection. Kim said early testing suggests users need a 6 to 10 megabits per second connection to get the instant play.

Also being added to the 360 is the Last.fm music service.