From HTML to XHTML
Still writing your documents in html? if you are, you're not complying with current standards. on january 26, 2000, xhtml 1.0 became a recommendation by the world wide web consortium (w3c). html, according to the w3c, is no longer the web markup standard. instead, xhtml 1.0 has replaced our old favorite, marking up the dawn of a new and exciting time in communications technology.f
http://www-106.ibm.com/developerworks/library/w-xhtml.html
The XML bible
Cafe con leche
is the preeminent independent source of xml information
on the net.
cafe con leche is neither beholden to specific companies nor
to advertisers. at cafe con leche you'll find many resources to
help you develop your xml skills
here including daily news summaries,
examples, book reviews, mailing lists and more.
http://metalab.unc.edu/xml/
W3C specs
W3C specs
http://www.w3.org/tands/ql/ql98/pp/xql.html