With the emerging availability of small and portable devices that are able to determine their position and to communicate wirelessly, mobile and spatially aware applications become feasible. These applications rely on information that is bound to locations. In this paper we present Nexus, a platform for such applications, which is open for both new applications and new information providers, similar to the World Wide Web. Distributed servers provide location-based information, which is federated to an integrated view for the applications. To achieve this goal, we present the concept of the Augmented World Model, which is a common data model for location-based information. We give an example to show how applications can use this platform.