Our sister site, AjaxDeveloper.org, has posted about the last in the series from DevArticles about the creation of an Ajax-based chat with the help of PHP.

In this third and final part of a tutorial that explains how to build an AJAX-based chat application, Alejandro Gervasio covers creating the PHP files that directly interact with a MySQL database, adding and fetching chat messages. He also makes some suggestions for expanding the functions of the application.

All of the code is done in PHP, so it's pretty simple to get working (even if you need to translate it over). It basicly inserts each message into the DB and then pulls it back out to display the latest messages...