On The Web Squeeze blog there's a recent post looking at a PHP framework that doesn't get mentioned that often (at least these days) - Prado. The post looks briefly at the framework at getting it set up for development.
This [word game] project was going to be slightly larger, and writing everything myself from scratch would have taken far too long. So I decided to use a PHP framework. PHP frameworks are a collection of code, meant to make your life easier and to aid you in the rapid development of dynamic websites. My choice fell on the Prado framework (see www.pradosoft.com).
He walks you through a first example script with both sides - controller to create/gather the content and the custom tag markup for it to inject the content into. He also includes a look at some of the Ajax support included with the framework. His example is the user clicking on a "Add to Cart" button to call the backend "onToCartClicked" method.