Yahoo has released the Yahoo search api. It is RESTful and does not use SOAP or WSDL. WSDL 2.0 has tried very hard to model RESTful Web services. For some reason Yahoo provided their documentation in text form as well as a schema for the response, they didn't provide a WSDL 1.1 or WSDL 2.0.
I quickly wrote up the WSDL 2.0 for their service.
It could be simpler, but it certainly seems to do the job.