SQL Injection Cheat Sheet : Samples are provided to allow reader to get basic idea of a potential SQL Injection attack and almost every section includes a brief information about...
atoum : A simple, modern and intuitive unit testing framework for PHP!
Software Folklore : Sometimes bugs have symptoms beyond belief. This is a collection of such stories from around the web.
Fat-Free Framework : A powerful yet easy-to-use PHP micro-framework designed to help you build dynamic and robust Web applications - fast!
drupal.org : Drupal is an open source content management platform powering millions of websites and applications. It’s built, used, and supported by an active and ...
This is a collection of known design patterns and some sample code how to implement them in PHP. Every pattern has a small list of examples (most of them from Zend Framework, Symfony2 or Doctrine2 as I'm most familiar with this software).