Web services are self-contained applications that can be located on and invoked over the Internet. Because web services are built with standards such as XML, SOAP, UDDI, and WSDL, they are platform-neutral. For example, a sales rep may visit a local buyer who wants to order 10 copies of a book. Rather than waiting until he gets back to the office to place the order, the sales rep can review the inventory of the warehouse on his PDA using a...