Another approach on introducing XML to PHP programmers is done in this book from New Riders. It is not as buzzword compliant as the Professional PHP 4 XML book from Wrox, but still comes rather close.

The first chapter introduces you to the basics of XML, together with some vocabularies that are introduced first. Instead of going into the basic PHP syntax, this book omits it and only gives some basics on what PHP actually is.

After the introduction, the book has two chapters describing the two methods of parsing XML: SAX and DOM. These two chapters are highly decorated with examples, which give you a clear understanding of the presented methods. The next
chapters describe basic XML vocabularies: XSLT, WDDX and RPC. The XSLT chapter is very flimsy, it does not deal with XSLT templates at all, only on how you can use PHP to apply XSLT on your XML files. It does this in great depth though. The WDDX chapter first describes the basics of WDDX and then explains how to use WDDX serialization with PHP. As example here, the author shows a simple client/server example, which communicates through WDDX packets. Then RPC is introduced, both XML-RPC and SOAP are covered again with lots of examples.

Chapter 7 covers PHP, XML and Databases. It deals with exporting a database as XML and importing XML into a database. With these conversions, techniques from earlier chapters are used, such as XSLT and SAX. Chapter 8 covers alternatives to parsers and convertors in the form of PHP scripts and classes. Most of the presented code is only really useful when certain XML/XSLT functions are not enabled in your PHP build, exactly as the author
writes in the introduction of the chapter. Alternatives for XML-RPC, XPath, DOM and SOAP are presented in this chapter. In the last chapter, a case study is done with the help of Metabase, the predecessor of the MDB PEAR package.

XML and PHP covers the basic things to process XML with PHP, but is not covering the used technologies like XSLT and XPath at all. Therefore, I would not recommend this book for people with no previous experience with any of the presented XML vocabularies. However, if you are an experienced user of those technologies, this book will teach you how to process XML and related technologies efficiently.