This Russian site has all the details needed to upload new maps to a Magellan eXplorist 300, 200, or 100. Inside the battery case are four pads that can be used for serial communication.

Magellan's new $699 RoadMate 360. It features a 14-channel GPS receiver based on Hertz's NeverLost system and street maps for Canada, Puerto Rico, and all 50 U.S.