Michelangelo van Dam had done some preparation for when he took the PHP 5.3 certification exam - he passed - and has written up a new post to his blog to talk about some of the things he did to help him study and prepare himself for the exam.
Before starting the exam, I had to sign a non-disclosure contract with Zend Technologies, Inc. to keep the contents to myself, so don't ask me what questions were asked. I can write a short article on how I prepared myself to pass the exam and what you can do to achieve the same successful outcome.
He gives links to and mentions several of the resources he used to learn all he needed like the official Zend PHP 5.3 Certification Guide, the PHP.net site for reference on several sections that were more PHP 5.3-specific (like namespaces, DateTime and Streams).