The ``Internet of Things'' intends to enhance items of our everyday life with information and/or processing and interconnect them, so that computers can sense, integrate, present, and react on all kinds of aspects of the physical world. As this implies that enormous numbers of data sources need to be connected and related to each other, flexible and dynamic middleware support essentially providing zero-programming deployment is a key requirement to cope with the sheer scale of this task and the heterogeneity of available technologies. In this paper we briefly overview our Global Sensor Networks (GSN) middleware which supports these tasks and offers a flexible, zero-programming deployment and integration infrastructure. GSN's central concept is the virtual sensor abstraction which enables the user to declaratively specify XML-based deployment descriptors in combination with the possibility to integrate sensor network data through plain SQL queries over local and remote sensor data sources. The GSN implementation is available from http://gsn.sourceforge.net/.