Builder.com has one nice page in "20 Questions about HTML" that runs through
the basic page code.
http://www.builder.com/Authoring/Basics/ss09.html
Web Design Group's guide
to HTML 3.2 - This site lists HTML codes both by where they are used
in a document and alphabetically.
http://www.htmlhelp.com/reference/wilbur/
The Bare-Bones Guide to HTML 3.2
- This guide has HTML references in several languages
http://werbach.com/barebones/
HTML Quick Reference
Guide - The chief advantage here is that the whole thing is on one page,
i.e. it can be printed out and kept by your computer.
http://www.cc.ukans.edu/info/HTML_quick.html
The W3C is the horse's mouth for
all HTML questions. Visiting their site is a sort of pilgrimage for web
developers. You don't have to go often, but you do have to go some time.
http://www.w3.org/MarkUp/
HTML 4 references are covered in the section
on HTML 4.