In part seven of their "PHP 101" series, Zend has a new article posted about The Bear Necessities concerning PHP classes/objects.

So now you know how to create your own functions in PHP, and you've spent the last few days busily inspecting your applications and turning repeated code fragments into functions. But functions are just the tip of the software abstraction iceberg. Lurking underneath is a three-letter acronym that strikes fear into the hearts of most newbie programmers. OOP.

They follow through on the subject, beginning with what a class is, how it's structured (complete with sample code), the types of methods (public, private, protected) and much, much more. This article is a very good alternative to most of the overly simplistic ones out there. They provide not only a good overview, but go into details on PHP 5 features some may not be familiar with.