With a "post-exam post" today, Jad has come back from the testing center fresh out of the new Zend PHP5 Certification exam with a few comments.
I just came back from the test centre; The exam was really great and joy to take, all topics were equally covered but if you are planning to book then I'd suggest not to make a general read but read in details about everything even stuff you aren't likely to use or you are not used to use in your daily dose of code.
He gives examples of questions of different types - syntax, general functionality differences, differences between PHP4 and PHP5, etc. He also specifically mentions some of the questions covering exceptions, SOAP, inferfaces, SimpleXML and more. He recommends reading up on pretty much every topic on their list.