This was just announced at E3 (I was watching a live stream of the Microsoft conference), so news of this should trickle out over the coming weeks. Hit google if you're keen to know more before my rant about it (probably won't make sense otherwise).
Personally, I don't see it doing much. Everything they showed was either mock-up "this is our vision" stuff, or really lame and simple interactive "toys", no actual gaming content to be had. Some woman playing a barely 3D breakout type game in which she just flailed like a drowning monkey in front of the camera/sensor in order to progress in some randomly un-challanging way, and they they show, wait for it, a painting program! In which some guy spent ages painting a terrible image with hand jestures that I could have done with a mouse in a 10th of the time.
They claimed it was a full 3D sensor and all that, but they failed to show anything that was much more complex than what's been done with pre-existing camera-input as controls for consoles like the Sony Eye-Toy.
They certainly tried damn hard to sell it though. First they had Spielberg up on stage, what he has to do with gaming I've no clue, but he waffled on for a bit about lofty ideals and basically just greased you up for what was to come, what he said was insightful and it sounded good but he wasn't really talking about games, just taling around them.
Next they had had Peter Molyneux from Lionhead (Fable) up on stage and if there was ever a man who could crap on about how great something was when it truly wasn't, this is he. So Pete waffles for a tad then shows a "video" of some interactive boy you could talk to and, err, interact with. They made it look like you could have a real conversation with him, but we all know scientists have been trying to create conversant AI's for years and haven't really gotten anything convincing yet - this was all just clever smoke and mirrors (wasn't live, was just a video). At one point the person interacting with this boy draws a picture and holds it up to the sensor bar to "hand" it to him and stuff, he wanted a picture of a fish and saw that it was a fish, but all I want to know is what happens If you hold up a centrefold from playboy magazine, if he reacts correctly to that ~then~ I'll be impressed, but until they stop overselling
it and we see some real games with it, I'm calling shenanigans on all of this.
It could be a good little accessory and a fun alternative way to accomplish a few simple things but honestly I think they need to dail down their "BS" meter on this one quite a few notches before I start taking them seriously about it.