Progress lives from the exchange of knowledge.
—Albert Einstein 

Helps & Hints

One of the handiest tools I use is the Chris Pederick's developer's tool bar extension for Mozilla Firefox. It is a dream in that you can outline elements of pages such as tables & divs, or display CSS class names and IDs. You can edit CSS styles real-time and view the changes. I highly recommend it. It's free.

Links, blogs, wikis, and other resources

Web Standards
W3C
"The World Wide Web Consortium (W3C) develops interoperable technologies (specifications, guidelines, software, and tools) to lead the Web to its full potential. W3C is a forum for information, commerce, communication, and collective understanding."
 
The Web Standards Project
"The Web Standards Project is a grassroots coalition fighting for standards that ensure simple, affordable access to web technologies for all."
 
Developing With Web Standards: Recommendations and best practices
A very well written and documented overview of Web standards. "This document explains how and why using web standards will let you build Web sites in a way that saves time and money for the developer and provides a better experience for the visitor."
 
Max Design: The benefits of Web Standards
A presentation about Web Standards; informative, concise information.
Tutorials
Project Seven: pvii tutorials and articles
Tutorials and articles about CSS and more.
 
WESTCIV: Web standards software and learning.
Collection of tips, tricks and quick tutorials regarding CSS - some more extensive tutorials & books are available for purchase.
 
www.maxdesign.com
Tutorials and articles about designing with Web standards.
 
Web Design References (University of MN)
Links to just about any subject relating to Web design: Accessibility, CSS, Information Architecture, Usability & much more.
Browser Screen Shot Tools
Test your layout in Safari with www.snugtech.com
Another test for Safari from www.danvine.com
Test layout in IE7 with www.danvine.com
Test layout in multiple browsers with www.browsershots.org (This site takes awhile & sometimes browsers are unavailable; try it on weekends.)
Blogs, Wikis, Site Resources
A List Apart - By Jeffrey Zeldman.
Web design news, info, and insights since 1995 - not updated as often as in years past, but a great resource. Search the archive or browse by subject.
 
CSS-Discuss
A discussion list (very active) and wiki with resources/links that explain just about any CSS issue imaginable.
 
position is everything
Lots of CSS information, explanations, tutorials, helpful tips, tricks and hacks.
 
Quirksmode
Site explains many of the quirky little things Internet Explorer will implement incorrectly.