While doing development on a web services project, I needed a utility for making client requests quickly to verify the WSDL being produced. Using SOAP Client I can plug in a URL, have it parse the WSDL, and expose the methods for direct calls. Another cool thing is the option to add arbitrary HTTP headers to the request. One of the headers I added was for HTTP basic authentication. It's quite easy to construct the Authorization header value using this pseudo-code "Basic" + base64(username + ":" + password). The SOAP Client utility is a simple, open source Mac OS X native application. I have used the oXygen WSDL tool in the past, but it's just too cumbersome.