I assume that you are referring to a description of the WSDL service that does not exist in the WebAPI as such. Now I see that you also added a REST tag to this question, and I would like to emphasize that the WebAPI does not apply REST methods.
REST is in the middle of a discussion lately, but I think everyone agrees that it does not define any wsdl-like service.
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: http://en.wikipedia.org/wiki/HATEOAS
REST - , SOAP, , , , //.. , : -)
, webAPI - , wsdl.