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...
PHP Quick Profiler : A tool for quickly profiling variables and resources used by PHP.
The CMS Matrix : CMSmatrix lets you easily compare the features in over 1200 content management system products. Check the boxes next to the software you're interested...
OWASP : The Open Web Application Security Project (OWASP) is a worldwide not-for-profit charitable organization focused on improving the security of software.
Gophercises : FREE coding exercises for budding gophers
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).