<p>Can anyone point to live examples of SOAP or REST web services? How do you use or test an existing web service with a client?</p>

A SOAP webservice which converts the temperature Celsius to Fahrenheit and other way around
http://www.w3schools.com/webservices/tempconvert.asmx
A description and source code is here
http://www.w3schools.com/webservices/ws_example.asp