Did you deploy the war and then start jbossas? If so, you might try starting jbossas first and then deploying the war. I have had problems deploying web services on 5.0.beta4 if I deployed them before starting the server.
For a complete example, see http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4153688#4153688. Yes that is an EJB, but just remove the @Stateless annotation and package it in a war and you have a POJO web service.
I tryed deploy my war folder after jboss start and this works well!!
Thank you Peter!
I hope jbossAs 5 beta5 (or RC1) will solve this point.