In this paper we present a multi-modal web interface for autonomous mobile robots. The purpose of this interface is twofold. It serves as a tool for task supervision for the researcher and task specification for the end-user. The applications envisaged are typical service scenarios like remote inspection, transportation tasks or tour guiding. Instead of post-processing a huge amount of data gathered and stored during operation, it is very desirable for the developer to monitor specific internal variables of the target system in real-time. Sensory information on several levels of abstraction are visualized using state-of-the-art web technology yielding a plug-in-free interface which can be viewed with a standard browser. It provides multi-modal information in several representations: off- and on-board vision, laser and odometry. This tool proved to be indispensable in the developing phase of navigation algorithms for localization, map building, obstacle avoidance and path planning. Modern guidelines for ergonomic interface design like context-sensitive popup menus or clickable goal specification make the interface very intuitive for the end-user. Its practicability is extensively demonstrated in the \'Computer2000\' exhibition event, where during 4 days the robot was remote controlled in a fully autonomous mode by visitors of the tradeshow using this interface. Keywords: Multi-modal interface, web interface, task supervision, task specification, mobile robots, remote inspection.