MacProtect for Mac

From Red Byte Software:

Don't leave your Mac out of your sight! Everywhere you'll find people that wait for you to leave your mac alone, so they can spy out your very private data, no matter if it is your Powermac at work or your new Powerbook you are carry with you. With MacProtect you can protect your Macintosh! After installing and defining a password your Mac will demand a password after every startup, so only with the right password users have the chance to use the Mac. If unauthorised users try to login with a fake password, MacProtect will log the login-attempt and writes it into a textfile, so you can check if any unwanted persons tried to login and what password they used.