Secure Login is an application that give you password protection for your templates. Users are assigned access levels (such as Administrator, Manager, etc.) and when the user logs in, his access level determines what pages he is allowed to see. You can even use this system to show different areas of content on the same page to different levels of users. (eg. perhaps you want managers to see a set of links, but you want administrators to see additional links.) Comes with an Access database.
Webmaster Scripts > Script Directory > Web Scripts
