I was delighted to be invited to by Think Vitamin to become a regular staff writer for the site. We started out with a series of articles about Object Oriented PHP, beginning with the basics and working through to some quite advanced concepts. There were five posts, these all went offline in mid 2012. I have reposted some of these on my blog, but get in touch if you want/need the others.

Getting Started with OOP and PHP5
Getting Started with OOP and PHP5: Part 2
9 Magic Methods for PHP
Exception Handling in PHP 5 (currently unavailable)
OOP in PHP: Finishing Touches (currently unavailable)