On the Zend Developer Zone, there's a spotlight on a book from APress and a sample chapter that's being offered - "Pro PHP XML and Web Services" by Robert Richards.

Robert Richards and Apress have published a definitive tome on PHP and XML. This is one of the few hard-back technical books I have in my library and it truly is an impressive work. I won't take the time to review the entire book here because I'll be doing that in the coming month but I will setup the chapter they sent us with a few words and a quote.

The sample chapter [pdf] takes a look at the XMLReader functionality built into PHP5 - an immensely useful tool for parsing any and all XML simply.