In addition to what William mentioned, as far as I know, you really don't need to have a wsdl at all. If you have xsd that defines the document structure. Still you can create webservices and clients. Spring does it. Ofcourse, you can still see WSDL if you wish to , if you append ?wsdl to the service url.
There is another thread , which talks about same topic.
However, I do have a question to William. Do we need to have WSDL, if we are required to use other WS standards like security, reliable messaging etc.
If we can create a valid SOAP request other mean like using JDOM etc with all the elements, can we not post the SOAP message to the service and still get it to work.