Login
PHP Login System with Admin Features. A tutorial and script to create a members area of a website and administrate those memebers.
A step through guide to a simple PHP script for user authentication for an area of a website. There is also Php-mysql-tutorial.com - Better User Authentication : Storing user id & Password In Database.
How to implement session tracking using two of the simplest and oldest methods available to programmers.
Simple login, logout, and session handling
An overview of a simple method to authenticate users. Acts as a great tutorial to understand the process.
An overview on how to immplement a user authentication system and download files with admin features so you can adapt it for your site.
A guide to session handling using PHP4.
The PHP.net 'session handling functions' section of the PHP manual.