While
I think that everyone should know (and love) XPath, it looks like XQuery is
going to be the next item that you’ll need to know in order to query XML
docs, Yukon, System.XML (?) etc. The great thing about XQuery is that you get
XPath strengths with SQL like statements (FLWR expressions). Here’s
a fine article that covers the basics of XQuery for you.
http://tiberi.us/view_article.aspx?article_id=26
Sean