The pervasive and mobile computing scenario is characterized by the high heterogeneity of devices used to access services, and by frequent changes in the user's context. In this paper we present an architecture, realized on top of two existing frameworks, whose main goal is to support the provisioning of advanced, context-aware Internet services in such a scenario. In order to demonstrate the feasibility of our solution, we have developed a prototype location-based service addressed to mobile users that takes advantage of this architecture.