Microsoft CEO Steve Ballmer opened up the largest consumer technology trade show in the world, the Consumer Electronics Show, with a talk that mostly revolved around Windows 7 and strides in computer gaming. And he said Natal would be ready by Christmas.

Microsoft announced Project Natal at E3. The new controller-free video gaming system, which reads a players body movements with cameras and mimics them with avatars on screen, will be available for purchase by the holiday season this year. Microsoft did not say how much the system would cost, but again stressed that it would work with all existing Xbox 360s.

Robbie Bach, Microsoft's president for entertainment and devices, also announced a new edition of the popular game Halo, which is due out in the spring. "What Star Wars is to film and what Harry Potter is to fantasy books, Halo is to the gaming industry," he said.