Where to start with OOP PHP

I have been using php for a little while now and would like to learn more about the OOP side of PHP. I am wondering if anyone could suggest a good book, site, tutorial, or any information that might help me out on learning more about this subject.

Thanks in advance!

See the manual:
php4 - http://www.php.net/manual/en/language.oop.php
php5 - http://www.php.net/manual/en/language.oop5.php
(exceptions - http://www.php.net/manual/en/language.exceptions.php)

and get any decent object oriented coding book (even a java book since the concepts are the same). We also have a oop tutorial on this site in the tutorials/basics section. Remember - learn the concepts (objects, methods, encapsulation, inheritance, polymorphism, ect.) because they are non-language specific.

maybe also check out here - http://java.sun.com/docs/books/tutorial/java/concepts/

Hope that gives you some direction. Good luck!

Are you using php4 or php5? I've been reading a lot and from what I read, if you are still using php4, it isn't worth you're while to use the OOP...