Sample SharePoint web service calls using the Instruction Framework.
The sample uses the SharePoint Search Web Service available in SharePoint 2010/2013 Server
The sample uses sql query syntax.
If you are using WSS/Foundation you need to target a different web service: Windows SharePoint Services Query Web Service
More info here: spsearch.asmx vs search.asmx .
The AuthenticationHelper class of the Instruction Framework makes it easy to authenticate in other scenarios.
The sample below shows how to connect via fba or claims authentication.