CodeDom API + PropertyGrid = Web Service GUI (wizdl)

This open source utility allows you to quickly import and call methods on any web service using a dead simple GUI. Supports web service methods having complex parameters and return values. The C# implementation details are as follows: Use ServiceDescriptionImporter to generate proxy classes from WSDL Tweak the proxy classes and promote fields to properties so that they show up in a property grid Make properties fully editable using a couple of custom UITypeEditors