I'm pretty much using: www.php.net - has all the PHP documentation, plus a lot of helpful comments from other coders (read the comments AND the manual, because sometimes the manual is off-beam) www.mysql.net, which is the official site of MySQL http://javascript.about.com - has a lot of information on how to write Javascript, and is different from... http://javascript.internet.com, which has a lot of pre-built code for you to use.
Also, anyone who's using MySQL databases should use phpMyAdmin, which can be downloaded from PHPWizard.net, and allows a lot of the more complex database functions (i.e. the ones that can really screw the database) to be carried out automatically. Also allows you to check the syntax of your MySQL queries.
When I was first starting out, I used http://builder.cnet.com a lot, they had good tutorials on HTML design and Javascript stuff.