In this new tutorial from WebReference, they show you how to develop a simple database-enabled Ajax application in PHP.

In this article you'll learn how to create database-enabled Ajax requests using PHP and MySQL. We begin by creating the front-end HTML and JavaScript files used to make requests to the server-side. The requested server-side is a PHP file which bridges the gap between Ajax and a PHP object that connects to a MySQL database and returns results as an XML response to the Ajax engine.

The application is a simple way to enter news postings into a database and pull them back out with this handy Javascript functionality. They also provide the complete source code for download to help you get started.