XHTML isn't XML!!, if I understand you correctly...
take a look at http://www.w3schools.com/xhtml/default.asp
Now, XHTML is kind of replacement for HTML,
but XML is simply for storing data, XML can be used for web designing, but really not recommended like XHTML...
I would use XHTML but study it a little better, if you don't know what I'm talking about...
Hope it helps, Arni