This paper describes an approach on the way towards dynamically configuring an application by discovering and using smart devices in a sensor/actuator network. The key to this are self-describing smart devices. Self description means that all information necessary to use the respective device are stored within the device itself. As an appropriate description language XML has emerged during the last years. XML provides considerable flexibility and ease of post-processing using XSLT stylesheets. However, because of stringent space constraints, there is the need to have a more compact representation. We describe what information is stored, what it can be used for, and how we make this information accessible during run-time.