I removed the links for this comment as someone had posted a PDF that wasn't licensed to be shared. I agree with the advice though - the Zend Certification 5.0 Study Guide from php architect is probably the nearest thing to a good book you will find for ZCE. It's out of date but the bulk of the syllabus remained largely unchanged. Ignore the PHP 4/5 chapter, and remember that there were many new features introduced in PHP 5.3 - mostly in the OOP area, so perhaps the ZCE 5.0 study guide plus a good OOP textbook for PHP? (You can of course buy my own book PHP Master (affiliate link), but there are plenty of other good options too!)