PHP is a web programming language that can be compiled into the Apache web server and with its persistent connections to MySQL it makes for a very popular and fast web programming environment.
- PHP Cheat Sheet
- Joseph Vaughan’s favorite articles on PHP security
- MVC frameworks for PHP (things like Ruby-on-Rails)
- Debian packages for bleeding-edge versions of PHP and other LAMP-related packages: http://www.dotdeb.org
- PHPunit – Unit Testing for PHP
- http://codepad.org/ – test snippets of code in PHP and many other languages.