PHP

Hardened PHP
Adds security hardening features to the language. Include news, libraries, Hardening patch, services advisories, a forum and a system for advanced protection of installations.
http://www.hardened-php.net/

International PHP Magazine
Web-based magazine for Web professionals focused on PHP based development. News, online articles, book reviews, forum.
http://www.php-mag.net/

PHP Club
A programmer's group united by a desire to develop PHP technologies in the Internet. News, articles, applications and FAQ.
http://www.phpclub.net/

PHP Everywhere
John Lim's weblog with comments and reviews. Links to his longer articles and manuals.
http://phplens.com/phpeverywhere/

PHPit
PHP and MySQL articles, tutorials and codesnippets. It also has database with commonly asked questions.
http://www.phpit.net/

PHPMac.com
Dedicated to PHP programmers that use the Mac OS, in particular Apple's OS X unix system. Tutotials, articles and support.
http://www.phpmac.com/

Quality Assurance Team
Volunteer coders dedicated to providing coders with quality assurance.
http://qa.php.net/

Making the Case for PHP at Yahoo!
Slides from a talk where Michael J. Radwin makes the case for using PHP over other languages. <small>(October 25, 2005)</small>
http://www.radwin.org/michael/talks/yahoo-phpcon2002.htm