Team S are remote from team C. Team S create a WCF web service with WSHTTP bindings. What's the best way for team S to share the interface specification with team C? In the days of asmx web services team S would have emailed the WSDL to team C. Is this still the way to go?
If the two teams don't have any online connection, one thing you could have Team S create a service client-proxy, possibly in a separate class library assembly, that imports the service (Add Service Reference in Visual Studio).
Just send that source code to the other team and they should be able to instantiate proxy clients and call methods on those clients.
If the two teams do have online connection, see Mikecito's answer - just navigate to the service URL + ?wsdl and you have your WSDL - always up to date, always current.