I'm happy to report that just this weekend I found out that I am among the first people in the world to pass the Sun Certified Web Services Developer for Java EE 5 exam (311-230). I took the beta exam back in November. Because it was in beta at the time, the exam took 4 hours, and then required a few months for the certification team at Sun to normalize the questions. Once they determined which questions to throw out, they determined passing and failing scores.
Even though it's multiple choice, this is a hard test.
Inadvertantly, my upcoming book Java SOA Cookbook (O'Reilly) will serve as a good study guide for the Sun Certified Developer for Java EE 5 Web Services test. If you're planning on taking the test, I suggest picking up a copy, as it covers many of the topics you'll need to understand thoroughly. You have to know WS-I Basic Profile, Security, and you really have to know XML, XSD, the new Streaming API for XML in Java, JAX-WS, REST, and the details and variants in SOAP and WSDL. Java SOA Cookbook covers much of this to the degree you'll need to know it to pass, and focuses purely on the EE 5 stuff.