Web services (WS) is emerging as the technology for integrating loosely couples applications employing three main protocols: WSDL (describing the WS), UDDI (publishing the WS), and SOAP (accessing the WS) using XML. WS could also be composed together to meet certain business requirements. Strategies for implementing WS include open source, such as XML and Java and product-based, such as Microsoft .NET. Each of these two strategies has advantages and disadvantages. Example of success stories of WS implementations will be given and analyzed. Potential applications of WS for intranet and internet platforms will be highlighted. The following is an outline of the tutorial: - Why we need WS - Loosely coupled applications - Definitions and basic concepts of web services: WSDL, UDDI, and SOAP - Assembly/Composite web services -WS implementation strategies, the Lego dilemma: - Standards-based: Open standards Java, XML - Product-based .NET - WS cases. - WS applications - Internet applications: virtual organizations, supply chain integration, and e-government, - Intranet applications: integration of enterprise different back-end databases to meet business needs. - Organization's readiness for WS