The IBM developerWorks website has a new tutorial for those looking to get into the powerful combination of Ajax and PHP - an introduction to creating Ajax-based websites with PHP.

Learn the process of writing Asynchronous JavaScript + XML (Ajax) applications using native JavaScript code and PHP. This article introduces a few different frameworks and application program interfaces (APIs) that reduce the amount of code you need to write to achieve a complete Ajax-based Web application.

They (briefly) explain what Ajax is and the benefits of it before jumping right in to a sample page. They go for the "manual first" approach so developers know to make basic connections with the XMLHttpRequest object and handle the responses. They do mention some of the libraries offered that help with the connections too (like jQuery, Prototype and Dojo).