It's easy to assume that everyone is already aware of this (the W3C), but if you didn't already, you will find it an invaluable bookmark in your browser. Technically The W3C (World Wide Web Consortium) is an international consortium where Member organizations, a full-time staff, and the public work together to develop Web standards. W3C's mission is:
"To lead the World Wide Web to its full potential by developing protocols and guidelines that ensure long-term growth for the Web."
Basically, since 1994 these guys have been drawing up, setting and revising what are regarded as the acceptable standards in web design, web development and web based code in general.
Who better to advise you on pretty much any web design problem or technique?
No one, that's who!
If you take a trip to the W3C Schools web site ( http://www.w3.org/ ) you will find answers to pretty much any web related questions you have, plus there are real-time, web based applications available to test your code (HTML XHTML CSS PHP JavaScript ..etc etc) for legitimacy and even accessibility.
