This is simply a list of places to look before you think about asking a question. If you can't find your answer at one of the following locations, then you can start thinking about asking your question

General how-to's/introductions
Pixel2Life.com

Php
PHP.net
PHP Wiki
WAMP Server*
PHP Triad*
Appservnetwork*

MySQL
Dev.MySQL.com

JavaScript
Quirksmode
JavaScript.Internet.com
JavaScript Wiki
JavaScript function reference

Misc
Google - Everything
Webmasterstop - Mod_rewrite

* = Used to develop web sites on your own computer. Just download and install the programs.

If you have any more good references, feel free pm me or another mod, and we'll add it to the list.. Make sure it's not a link to some tutorial site, but a site that's dedicated to that subject, or has an article with really great info on the subject.

Update: For those that use Firefox, heres a few plugins to make answering your questions a little easier.
Mozdev.org