Well after my laptop got stolen my mom bought me new one (very nice of her ) in vista it uses the build in webcam to login, very cool and handy can this be done in linux to?

Dunno, but then, you probably can never change your look/style/clothes, as your computer won't recognize you.

just kidding.

It works very well, I was really surprised, different hairstyle, hats, clothes, shaving, I really surprised....

If it can be, and I'm not sure - I know fingerprint can be done - you need to look at something relating with PAM to be able to login to the system. For example, fingerprint was done with pam_fprint in Fedora, but Ubuntu it was the pam_bioapi package (pam_fprint not in Ubuntu). I don't know if the bioapi is only for fingerprint scanning as I've not checked the package details.

But even if it's none of these, it will have to be something linked with pam to do it. Sorry can't help any more than that.