soapUI

http://en.wikipedia.org/wiki/SoapUI

soapUI is an Open Source Web Service Testing Tool for Service Oriented Architecture made for the Software Developers. There is also a Pro version that is released a commercial product. Its functionality mainly covers Web Service Inspection, Invoking, Development, Simulation and Mocking, Functional testing, Load and Compliance testing. Productivity enhancement features can be found in the soapUI pro version.