In hazardous situations, fire fighters are presented with a series of difficulties related to the coordination of several crews at the scene. This paper describes a possible solution for this coordination problem based on the integration of mobile communication terminals with positioning modules.The implemented system displays, in real time, the position of every user at the scene. It also allows the exchange of text messages and sketches, created by the users.The use of Personal Digital Assistants as the core of the portable units results in a user friendly interface with the system. The units are connected through GPRS/UMTS/Wi-Fi. Each user's position is provided by GPS.Positions and sketches are displayed over digitalized map images or satellite photos.Field trials, conducted at the faculty campus, are presented.