To better support location-aware applications for mobile users, we introduce "adaptive service binding middleware." Though location-aware applications are highly valuable for mobile users, this very mobility presents a significant challenge for application developers. Location-based services available in one region become unavailable or irrelevant in another region, making it difficult to provide a smooth and seamless user-experience. We introduce a general-purpose application infrastructure supporting both location-awareness and mobility. The ability to dynamically rebind to new services, triggered by changes in the user?s location, opens up new classes of location-aware applications. We describe the requirements that motivate such an infrastructure, and explain our architecture, implementation, and initial experience.