found this FREE software that allows you to login to win 7 (32/64bit) xp, vista etc with your webcam. Took about 10 seconds to set up and simply put IT WORKS and it works well.
i sat down several times and it automatically logged me in. Logged out and my GF sat in front of the camera and she could not log in (to my account)
Luxand - Blink! - Login to Your PC by Simply Looking at It!
i give it a 10/10 for simplicity, ease of use, and because its free.