On the Zend Developer Zone, there's a new tutorial covering the use of the Zend_Acl and Zend_Auth modules in the Zend Framework to create a simple user login and authentication system from Simon Mundy.
After submitting the initial example of how Zend_Auth and Zend_Acl could be implemented Gavin pointed out areas that weren't really addressed in my proof of concept and it could potentially confuse newcomers to the way MVC is utilised. I'd like to clarify that post to a) Address those concerns and b) see if there's any constructive criticism of the process that could benefit everyone.
He sets up the site layout (including where the actions lie) and defines some of the access rules the script will follow. From there, he creates a bootstrap file and an index.php to work with it. On top of this, he builds the key piece - the Auth.php - to handle the validation of the users.