In the last few years, robot teleoperation systems have been improved with the advances in computer networks, virtual reality and graphical user interfaces. However, teleoperation applications for multiple and different robots in networked virtual environments are not available for all kind of users. This paper presents a collaborative multiuser system for multiple simultaneous robot teleoperation. We describes the object oriented distributed architecture used and the system modules developed. The system implementation shows a visual simulation based on a networked virtual environment. The system allows different kinds of manipulators and mobile robots, either virtual or real. The feasibility of the system has been successfully demonstrated with some experiments.