SaVi 1.4.2, for Satellite constellation Visualization, is now available. SaVi lets you simulate satellite orbits and coverage, and includes simulations of complete systems such as GPS, Galileo, Iridium, or 03b Networks. SaVi needs only Tcl/Tk running on unix. 3D rendering of satellites requires Geomview, another SourceForge project.
SaVi 1.4.2 includes fixes for a couple of rare Tcl/Tk errors, makes -redrawn-menus the default on Mac OS X to work around a bug in using the 10.5 Leopard menubar, and adds a View Source... option.