OpenGTS is a full-featured GPS tracking system that includes the OpenDMTP server, yet also can support other remote tracking device types. It also provides a Web interface that provides GPS tracking and location reporting. Server configuration experience is required to use this.
Support for Microsoft Virtual Earth and other mapping service providers, support for multiple users per account, access control lists, better 'auto-zooming' for Google Maps, and better installation/configuration documentation (PDF file).
URL: OpenGTS - The Open GPS Tracking System