Over on Dynamically Typed there is a two posting series on efforts to get javascript to talk to PHP effectively.

In posting one, Harry talks about the deployment of such a system - in a Mechanism/Payload/Population system (or the envelope/letter/response). The idea is to make the web environment more seemless, similar to using a web-enabled desktop.

The second posting dives a little deeper into the actual workings behind the process, including sample javascript, SOAP functionality, and HTML/PHP examples to get you started.

There's lots of power here, between these two languages - the problem is just finding that harmony between them that works the best...