I mentioned my xmlP tree control as a code example and started getting lots of hits. But it wasn't really in any shape for public consumption. I fixed a couple of things and packaged all the required files into a zip. http://www.dorb.com/darrell/xmlP/
Also a screen shot http://www.dorb.com/darrell/xmlP/scrn.jpg the numbers to the right are the line number.
It will view anything with tags in it. Things like this aren't handled: <![CDATA[ expr="age > 18" ]]> That came from the Zope site, so I have some more work todo someday.
If you have wxPython it should work at least as good as it does for me.
<P><A HREF="http://www.dorb.com/darrell/xmlP/">XMLTreeCntrol 0.1</A> - a simple graphical XML tree control for wxWindows/wxPython. (08-Jan-2000)