Functions and Classes in php
http://www.devarticles.com/c/a/PHP/Introduction-to-PHP-Classes-OOP/
http://www.techflirt.com/tutorials/oop-in-php/classes-and-objects-php.html
http://www.phpbuilder.com/columns/rod19990601.php3
SEO
SEO classes http://www.phpclasses.org/browse/class/149.html
Offline SEO http://www.phpclasses.org/package/4058-PHP-Generate-reports-about-Web-pages.html