Silentum LoginSys is terrific if you're looking for a simple, easy-to-install login system for your site. You assign the user name and password you want to use, then upload the two PHP files to your site, login, and you're done. This script can protect as many pages as you want by transferring a small piece of code onto each page, and can also be used as a great message board login system. A cookie is used to denote whether or not someone is logged in. No MySQL is required.