As a note to this, my ASUS laptop has this technology installed and it is VERY cool. To set it up it took several photos of me (double digits) and I found that the more varied lighting conditions you use the better and then it asked me for a "back up password" and it was good to go.
In practice, this works much better than I ever thought possible. When the laptop boots up the webcam activates and begins searching for my face. As soon as it sees my face it locks on and logs on. It is typically faster than me typing in the password (which it has the option of up on the screen also). When the room is a bit dark (poor lighting) it sometimes takes awhile, but other than that it is almost always instant.
And I have not been able to fool it yet. I have tried pictures and videos of myself, but nothing seems to trick it (I got curious about this too). It doesn't even have issues when I grow out my beard in the winter. The technology is much more sound than I ever would have given credit for.
I don't know if I'm willing to give up my current hacked lockscreen for this, but I might just to have it available (and as long as they can match the abilities of my two year old laptop). I just wanted to answer some of the questions I saw popping up.
Oh, and my laptop also has "fingerprint scanning" to unlock too, but it doesn't work nearly as well as the face recognition. It is much more finicky and slower.
My half a nickel.
K--