Here are the top ten sites (we have 9 so far, and others can be added later) I use when developing in PHP, CSS and/or HTML
- World Wide Web Consortium (W3C) - Here there is a lot of info about many subjects, HTML, CSS, XML, DOM (used in javascript), etc
- W3C HTML definition - The HTML definition used by most of today browsers
- W3C CSS definition - The CSS definition that is common to most browsers
- css Zen Garden: The Beauty in CSS Design - top pick for examples of exactly what you CAN do just by changing CSS and writing well-thought-out (d/x)HTML
- A List Apart - when you're done gawking at css Zen Garden, drop by A List Apart for real-world CSS recipes
- CSS/edge - Eric Meyer's creative experiments with CSS to produce pure CSS menus, complex layouts etc.
- PHP Related
- PHP documentation - PHP documentation
- PEAR (PHP Extension and Application Repository) - a framework and distribution system for reusable PHP components
- PHP Builder Articles - articles about PHP related material, from code design to code examples and php tips
- IE javascript (MSDN) - Documentation about IE javascript
- Mozilla javascript - Documentation about mozilla (and firefox) javascript
- W3 Schools - Decent references for many web-related languages, including HTML and CSS. Handy for "Is it 'color' or 'font-color'?" Also has "try it yourself" tutorials which are good for getting a feel for something but won't take you beyond that.
- Google - You can find a lot of information with google
- http://www.webmasterworld.com - This is pretty much the forum-based resource for webmasters. Many different forums on everthing from php and CSS to SEO and marketing. Very active.
- Design & Template Related
- Open Source Web Design - Tons of layouts donated to the project, some truly open source, some require a creative-commons-like By attribution to remain on the page. Watch out for licensing issues.