Which version of the exam, the old one or the new one?
Joined: Jun 16, 2009
For the new one Sun Certified Developer for Java Web Services 5 (CX-310-230)
Joined: Oct 04, 2006
Well, then there is no single book that will guide you through the exam.
Despite its age, J2EE Web Services by RMH is still a good introduction to web services. Skip the parts on JAX-RPC.
Java Web Services Up and Running will provide an introduction on JAX-WS etc.
Here is another book that speaks about endpoint design etc: http://java.sun.com/blueprints/guidelines/designing_webservices/ Of course, do not forget the specification documents for the different specifications covered by the exam!