Cover Pages [ http://xml.coverpages.org ]
A comprehensive, online reference collection supporting the XML family of markup language standards, XML vocabularies, and related structured information standards.

Python and XML [ http://pyxml.sourceforge.net/topics/ ]
The home page for XML processing with Python.

XML Sitemaps [ http://www.xml-sitemaps.com/ ]
XML-Sitemaps is a free service which enables you to create Google XML Sitemaps online.