Sites with HTML reference information

html reference
Xhtml.com - XHTML reference
A clear reference guide taking you through the various aspects of XHTML tags. And alternative is Topxml.com's XHTML reference - A glossary and reference guide for HTML tags and events and their validity for XHTML.
Eskimo.com - HTML Quick Reference
Web based quick reference cards for HTML.
Digilife.be - Quick Reference Cards
Web based quick reference for HTML tags and other programming languages. There's also: Petefreitag.com - Devloper's cheat sheets roundup.
Creativecommons.org - resources
Sharing and reuse of cultural, educational, and scientific works.
Webstandards.org - Named Entities
A list of the named Entities in HTML (e.g. nbsp;). This site has a reference tool to help find XHTML character entity reference: digitalmediaminute.com.
Javascriptkit.com - htaccess
An overview with tips, explanations and examples on using the .htaccess file. See also: My.execpc.com - About htaccess and XBitHack
The CGI Resource Index
A reference site for CGI. See also: Taxpolicy.com - An introduction to using CGI.
Webcom.com - Changing Permissions with FTP
An overview of the basics of changing file permissions using an FTP client.