Although, we can easily find Web services and determine their interface and the message formats they understand, actually calling a Web service requires carefully studying its documentation and then writing special-purpose code to handle the service. As a further obstacle, no standards currently exist for making a service accessible through a Web browser. To solve this problem, we designed an XML-based approach that makes creating user-friendly, browser-based GUIs for Web services a straightforward task. We also created a prototype system that implements the approach called WSGUI, which is short for "Web Service GUI."