An XML library for PHP you may not hate.

http://evertpot.com/an-xml-library-you-may-not-hate/

XML with PHP

http://phpmaster.com/bending-xml-to-your-will/

PHP Dom working with xml
http://phpmaster.com/php-dom-working-with-xml/

 PHP DOM working with XPath
http://phpmaster.com/php-dom-using-xpath/?utm_medium=email&utm_campaign=Five+Creative+PHP+Snippets+XML+Wizardry+with+XPath+and+Manage+Your+Class+Dependencies&utm_content=Five+Creative+PHP+Snippets+XML+Wizardry+with+XPath+and+Manage+Your+Class+Dependencies+CID_9891ebab597beaca64e251bc7ed155ed&utm_source=Newsletter&utm_term=PHP+DOM+Using+XPath