On the PHP-Learn-it.com website, there's a new tutorial today about taking those first steps into combining PHP and Ajax to make a simple working example.

This simple tutorial demonstrates how to post a form using PHP and AJAX without having to refresh the page. A first step in becoming an AJAX developer.

They chose to go with the prototype Javascript library to use its included Ajax functionality. They give the complete code first then go back and explain the different parts - how it makes the request, shows the response back from the PHp script and what the PHP script actually does.