Xpath help!!!

I've taken a few tutorials and looked at a few examples. I guess what I don't understand is how it all fits together.

What I need to do is make it easy to update an XML file by using XPath's. So if a element that is used in multiple XML documents is updated, I'd only update it once and run a program that substitutes the XPath with the actual value in all the XML documents. I would also need to generate a report of what was changed.

Do I use just straight XSLT with XPath for this? Or do I need to code some java also?

I'm confused.

Feel free to jump in any time.

If you could point me to an example or something, that would be great.

Again, all I want to do is update an XML file based on the contents of another XML file and report the changes. Am I on the right path?

Not sure exactly what you want, but www.w3schools.org has a pretty decent run through of xslt.
http://www.w3schools.com/xsl/default.asp

You probably only need xslt, as long as the updates are not too function intensive.