Provision of services within a virtual framework for resource sharing across institutional boundaries has become an active research area. Many such services encode access to computational and data resources, comprising single machines to computational clusters. Such services can also be informational, and integrate different resources within an institution. Consequently, we envision a service rich environment in the future, where service consumers are represented by intelligent agents. If interaction between agents is automated, it is necessary for these agents to be able to automatically discover services and choose between a set of equivalent (or similar) services. In such a scenario trust serves as a benchmark to differentiate between services. In this paper we introduce a novel framework for automated service discovery and selection of Web Services based on a user?s trust policy. The framework is validated by a case study of data mining Web Services and is evaluated by an empirical experiment.