The emerging paradigm of Web services has been gaining significant momentum in the recent years since it offers a promising way to facilitate Business-to-Business (B2B) collaboration. However, it is not clear that this new model of Web services provides any measurable increase in computing trustworthiness. In this paper we propose a generic framework to control the trustworthiness of computing in the domain of Web services. A layered model is established to highlight four key elements: resources, policies, validation processes, and management. The robustness of this model exhibits its flexibility and extensibility. Examples utilizing our framework are reported.