The news came from an Italian ad for the product that was pushed out by Atlas, an ad agency owned by Microsoft. The news was originally broken on USA Today's Game Hunters blog in a post which has since apparently been redacted.
Joystiq also announced a list of the games that will come out with the dynamic gaming system. They include Kinectimals, an animal-raising game; Joyride, a racing game; Kinect Sports; Kinect Adventures, a rafting game; MTV Games' Dance Central. Disney and Star Wars-character games are in development.
Project Natal's unveiling is occurring this evening in conjunction, somehow, with the Cirque du Soleil.
More on the Seattle PI's Microsoft Blog.