A tracking system (10) for tracking movable assets (16) and several methods for using the system are provided. The tracking system includes a monitoring device (22), a tracking information network (20), a data communication network (18), a tracker tag (12), and a tracking information server (14). The tracker tag uses GPS technology. The tracking information server provides programmed instructions to the tracker tag in messages via a messaging system. The tracker tag selectively retrieves the messages from the messaging system. The tracking information server provides tracking information and related information to a subscriber. In one embodiment, the tracker tag is in communication with an Iridium satellite constellation (28) and tracking information is displayed to the subscriber when the asset is substantially anywhere in the world. In another embodiment, the monitoring device is in communication with the Iridium satellite constellation and tracking information is displayed to the subscriber when the subscriber is substantially anywhere in the world, preferably via the Internet (36).