The NETTUTS site has this new tutorial posted today about the creation of a site with a user registration and membership functionality built in.

A tutorial for the very beginners! No matter where you go on the internet, there's a staple that you find almost everywhere - user registration. Whether you need your users to register for security or just for an added feature, there is no reason not to do it with this simple tutorial. In this tutorial we will go over the basics of user management, ending up with a simple Member Area that you can implement on your own website.

They use a MySQL database to store the users' information, show how to create the login form to test the user's credentials and the registration form to make signup easy. They also thrown in a dash of CSS to help style the forms into something a bit more pleasing to the eye.