NETTUTS.com: How to Use CakePHP's Access Control Lists
If you're building a CMS, you'll probably need different user roles'"superusers, admins, users - with different permission levels. Too complicated to code? Enter CakePHP's ACL (Access Control Lists). With the right setup, you'll be checking user permissions with just one line.
They talk about what "access control lists" are but shows you an example of one including the database tables and the full scripts for the Users controller, a model to hook into the database and the view for output to the user. They include methods for denying access, checking permissions, and modifying a user's permissions.