PHPMaster.com: Bending XML to Your Will
If you've ever worked with the Twitter or Facebook APIs, looked at RSS feeds from a website, or made use of some type of RPC calls, you've undoubtedly experienced working with XML. [...] Knowing how to process XML data is a crucial programming skill today, and thankfully, PHP offers multiple ways to read, filter, and even generate XML. In this article I'll explain what exactly XML is, in case you haven't had any experience with it yet, and then dive into a few ways you can use PHP to bend XML to your will.
He introduces the concepts and syntax behind XML first for those not accustomed and quickly moves into the tools to parse it. First he looks at the XML Parser, an event-based parser, and SimpleXML, an easy way to access the contents of a well-formed XML document. Snippets of code are provided for each to show you how to put them into practice.