Semantic Annotations for WSDL and XML Schema Is a W3C Recommendation
http://www.w3.org/TR/2007/REC-sawsdl-20070828/
http://www.w3.org/TR/2007/NOTE-sawsdl-guide-20070828/
http://www.w3.org/2002/ws/sawsdl/
http://www.w3.org/2002/ws/

The World Wide Web Consortium today released “Semantic Annotations for WSDL and XML Schema” (SAWSDL) as a Recommendation. With these attributes, semantic annotations can be added to Web Services Description Language (WSDL) components for use in classifying, discovering, matching, composing and invoking Web services. The
companion “Usage Guide” is a Working Group Note that shows through examples how to associate semantic annotations with a Web service. Read about the SAWSDL Working Group and about Web services.