Cafe con Leche XML News and Resources - Designed to provide more or less daily news updates from and for the XML community. It is maintained by Elliotte Rusty Harold and modeled after his Java news and resource site, Cafe au Lait.
Charles F. Goldfarb's XML Times - The ultimate XML E-Zine, on this site you will find news, books, events, articles, knowledge, links hosted by the inventer of SGML and XML.
Extensible Markup Language (XML) 1.0 (Fourth Edition) - The Extensible Markup Language (XML) is a subset of SGML that is completely described in this document. Its goal is to enable generic SGML to be served, received, and processed on the Web in the way that is now possible with HTML. XML has been designed for ease of implementation and for interoperability with both SGML and HTML.
Microsoft XML Developer Center - Microsoft's XML page, this site provides white papers, tutorials, and a list of related sites.
The XML Cover Pages from OASIS - The Cover Pages is a comprehensive, online reference collection supporting the XML family of markup language standards, XML vocabularies, and related structured information standards. Edited by Robin Cover since 1986, this public access knowledgebase promotes and enables the use of open, interoperable, standards-based solutions which protect digital information and enhance the quality of data processing.
XML Hack - xmlhack was a news site for XML developers. This site distills news, opinions, tips and issues concerning XML development into a new portal. Many articles are archived here, along with links to standards, mailing lists, and XML websites.