TUAW has lately been trying to help you Secure Your Mac, and while a few options have been available, biometric security is one area in which the Mac has seemed to lag behind the Windows side. Now UPEK has released a preview of the Mac version of their Eikon Digital Privacy Manager. The software allows you to use the Eikon scanner to login to your account, control your Keychain, switch users, or lock down your Mac.
The Eikon scanner is a USB device which costs about $40 and only comes with Windows software. Once you have the scanner however, you can download the Mac Protector Suite Preview for free from UPEK. If security is a serious concern and passwords are getting tedious then a biometric solution like this one looks increasingly cost effective.