PHP
http://www.webmaster-talk.com/php-forum/78717-differences-between-php4-and-php5.html
http://www.hiteshagrawal.com/php/php5-magic-methods/exploring-magic-methods-in-php-5
Joomla MVC Architecture
http://www.vojtechovsky.net/joomla/component-helloworld-2-create-tutorial-guide-en.html
http://www.phpeveryday.com/articles/Joomla-MVC-Introduction-using-Model-View-Controller-P128.html
WordPress Templates
http://www.siteground.com/wordpress-hosting/wordpress-themes.htm?page=1
http://wordpresstemplates.name/
http://www.templatesbrowser.com/wordpress-themes/demo/
http://wptemplates.org/index.php?blockpage=4&cat=1