After some time of early experience Web Services are moving themselves from a new highly fragmented technology to a piece of nowadays infrastructures which promise to address various current challenges. These include especially classical issues of integration and data in a heterogeneous environment. The Web Service technology provides an open and technology-agnostic interface, and furthermore propels new usage paradigms in distributed computing infrastructures like Grid Services. Successful adoption of Web Service technology relies on the de?nition of interoperable architectural building...