Web services are a set of emerging standards that enable
interoperable integration between heterogeneous IT processes and
systems. You can think of them as a new breed of web application
that is self-contained and self-describing, and that can provide
functionality and interoperation ranging from the basic to the
most complicated business and scientific processes. In short,
web services hold the promise for providing a common standard
mechanism for interoperable integration among disparate systems,
and the key to their utility is their standardization. This
common mechanism for delivering a "service" makes them ideal for
implementing a service-oriented architecture (SOA). Besides
using the common web transports, web services also require a
common language for the data exchanged -- Extensible Markup
Language (XML). Of course, XML is just the scaffolding for the
actual exchange. For the web services protocols to be
interoperable across diverse systems and suitable for serious
applications, standards bodies, suc