As part of the move to ubiquitous computing, sensor networks are an active topic for academic and commercial research. A variety of sensor network products and applications are appearing in the market. Environmental monitoring is a major application field for sensor networks, and the end users of such applications are generally average disciplinary scientists, i.e. environment researchers or ecologists. However, most current commercial sensor network products need extensive secondary development for adapting to different circumstances. This process, including replacing, adding, configuring and calibrating sensing elements, and configuring the network, is a difficult task for untrained end users. This paper introduces an ongoing project - Underwater Sensing Platform Network (USPN) - being developed at the University of Queensland which focuses on improvement of sensor network usability by providing a truly smart, plug-and-play sensing platform. Our approach is to investigate a novel architecture of a sensing node supporting different sensors and communication channels based on plug and play functionality to simplify the building and configuring process and to reduce the complexity, time and cost for deploying an environmental sensor network. The paper will describe both the system specification for the USPN plug-and-play marine sensor system, plus an initial system design.