On the Ibuildings techPortal today they've posted the latest podcast recording from the 2009 Dutch PHP Conference sessions, Paul Reinheimer's look at maintaining state with Ajax ("in an Asynchronous World").
This talk will examine the two greatest problems in Ajax development (except for that pesky browser issue): Exactly what that "Asynchronous" word means, what problems it creates, and how they can be effectively managed, next the YUI Browser History object will be examined, finally handing control of Ajax applications back to the user via their familiar back button.
You can listen to this new episode in one of two ways - either by using the in-page player or you can download the mp3 directly.