On PHPGeek.com, there's a new post talking about the use of the AuthComponent for CakePHP for access control in your application. It's not a tutorial, but it does follow how the developer came upon the component and why they're using it.
Nearly everything that is built needs at least some level of authentication and authorization before users can be let loose to use it. Unfortunately, not only is there a lot of confusion out there on how to use it, but lots of poorly done, reinvented wheels out there because of it.
He points out the solution he came across via another article from the "Another Cake Baker" blog (lemoncake) show how to use the component for ACL in CakePHP 1.2.