Search Web Service
Microsoft SharePoint Server 2010 exposes its search functionalities through the Query Web service. This allows you to access SharePoint Enterprise Search results from client applications and Web applications outside of the context of a SharePoint site.
To access the Query service and its methods, set a Web reference to http://[site]/_vti_bin/search.asmx.
|QueryService||The QueryService class is the entry point for calling the SharePoint Enterprise Search Query web service.|