Links to useful pages

The following pages come highly recommended:

Quirksmode
This site contains lots and lots and lots of information on javascript, DOM and css. Including browser compatibility tables, benchmarks and in-depth knowledge that you won't find on any tutorial or snippets page. I tend to 'browse' it by typing something like "quirksmode event model" into google when I want to know about the javascript event model.
w3schools
The number one reference site for html, xhtml, anything xml, css, and basic javascript. It also contains accurate though not very comprehensive articles on php and other scripting languages. It's also the site I browse back to anytime I forget a bit of SQL syntax.
php.net
Few programming languages come with a 'help' button. PHP on the other hand, has this comprehensive documentation at your fingertips. If the site is ever slow (something that'll happen with so many users) there's a "select mirror" button that can lead you to your local speedy version. I've never programmed anything without consulting their function list.
Apache documentation
Apache's documentation is very comprehensive, and tends to focus on issues for serious webmasters & performace. However, it's always right and comes with lots of relevant real-life examples and how-to's
Mozilla's Javascript reference
The "Mozilla Developer Center Core Javascript 1.5 Reference" (gasp) is my new favourite place for all things javascript. If something is going so amazingly wrong you think it must be a bug, check this site.
The Database Programmer
This guy knows about databases. A beautifully simple site with lots of articles explaining complex db concepts in a lucid manner.

Syntax Highlighting

GeSHi Generic Syntax Highlighter
Except for the php highlighting (which comes straight from php) all automated syntax highlighting on this page is created using the php library GeSHi. It's easy to use (2 lines plus a try catch block) and is freely downloadable under the GPL. As PHP programs go, this is a pretty cool one.

Shameless self promotion

Airglow Studios
My current employer, where I spend my days happily coding away building a game server, building sleek sleek ajax websites or talking about coffee.