Get There with XPathNavigator

In XPath Basics I gave a quick introduction to the syntax of XPath expressions to help the uninitiated get comfortable with XPath, which is a very important technology to understand for working with XML data of many forms. The thing about XPath is that it can't do anything on its own; it needs a processing engine to perform work based on the expressions. That processing engine could come in many forms.

http://www.aspnetpro.com/NewsletterArticle/2004/04/asp200404bn_l/asp200404bn_l.asp