AJAX and PHP

Yes, yes I know - an article on AJAX and PHP AGAIN? Well, to be frank, I think this entry will help for a beginner in understanding how to and where to begin when (s)he wants to start developing web applications.
I know that I am *quite* late in hopping on to the AJAX and PHP bandwagon. I have done a lot of Javascript and DHTML work, I have done a lot of PHP work (long long time ago in 2001). So let me set the requirements here. Steps to learning PHP and AJAX are:
1. Before you start learning about AJAX, you need to know what JavaScript and DHTML is. Start by building simple client only web pages based in JS and DHTML.
2. Once you do that, throw in some XML. This is where it gets a little complicated. XML, XSLT, XSL and who knows what. There is no end to it. Anyway, I think its best if you do some XML and some XSL and then using JS to parse the XML.
3. Now, you need to enter the world of PHP and server side scripting. You have to be very clear about how communication happens between the browser and the server, what is meant by HTTP requests and responses. Then, start by writing small PHP scripts which will communicate with the browser and show and take some data. In short, go about learning PHP the traditional way, that is, without AJAX in the mix. ( I am skipping setting up LAMP ). PHP.net has a tutorial for beginners, and so does Google.
4. Once you do that, go to the Mastering AJAX series, and read up. Its an excellent series of articles, which will help you get a grip on what AJAX is all about. Well, this is where I am currently at. I will update on more links once I do some more snooping around.