On the Solar blog there's a new post introducing you to a method for authenticating your users (of your Solar-based application) off of a MySQL database.

This entry is an extension to the current manual page for user authentication and is intended for folks who have already been through the basics of SolarPHP. What I hope to accomplish here is to show you how to setup user authentication using MySQL, something the manual currently does not elaborate upon.

He includes all of the bits you'll need to get it up and working - the code for the authentication, the configuration file setup, and the MySQL stable structure.