Bananscreen is a good program, but exist others perfect solutions
for example Veriface
I use
Rohos Face Logon
it compatible with Vista and XP, I like next features
1) last successful attempts to access the system by face are saved and stored,
2) it is possible hide video capture window during login by face,
3) Self-training feature
4) you may register faces of several people for one user account!