Free trial (30 uses) available at CNET’s download.com
I haven’t tried it but it looks well thought out and has some cool features. I like the feature where it takes a picture of anyone snooping around machine.
KeyLemon logs you in to your computer by using your face. More than just a glorified Webcam tool, it regularly checks to make sure that it really is you using the computer. The latest version of the app also comes with a neat Firefox plug-in called LemonFox, for added protection when logging into Facebook, Twitter, and LinkedIn.