Since IBM wants me to register to comment...
Wow, don't trust this. This is written by a Java person trying to infect PHP with their silly Enterprise nonsense. If you want to learn real OOP, start with an OOP language like Python instead of using PHP (which is a good language, no doubt, but as far as OOP goes it makes the same mistakes as those of the past). The very first piece of advice, using getters and setter methods, is idiotic and evil. Here's a post about that: http://www.thejach.com/view/2010/4/getters_accessors_and_setters_mutators_are_evil (Along with a third party comment to another such post.)
If any newbies want some real advice on PHP (I've been doing it for years), contact me and I'll happily give some!
Edit: Also, don't listen to 133794m3r. If he cared about speed he'd use Assembly, if he knew wtf he was talking about he'd know that procedural is one of the worst ways of programming and can make your code quite slow. Abstraction is good, use it.
I concur with the last post. Are there any other blog or other writings about this?