Web services constitute an important new class of software applications that can be programmatically invoked over the Internet. Fundamental features of web services include loosely coupled, layered, and ever-changing architectures that support user functions for large communities of users. The benefits of adopting web services include software interoperability and easy integration. Not surprisingly, much investment and effort is being drawn to the design and development of such services. In the meanwhile, goal- and agent-oriented design methodologies are getting more attention, as they enhance communication between business and technology worlds. This thesis combines these two techniques and proposes a methodology for designing web services and choreographing these services into business processes. The methodology is based on Tropos [Perini01, Castro02] that supports early and late requirements analysis, as well as architectural and detailed design. An online retailer example is used for illustration of the proposed methodology.