The original Mars Rover has been found. The high-resolution camera on NASA's Mars Reconnaissance Orbiter has imaged the 1997 landing site of NASA's Mars Pathfinder, revealing the current location of the Pathfinder mission's small rover, Sojourner. It has moved closer to its stationary lander after the final data transmission from the lander.
Pathfinder landed on July 4, 1997, and transmitted data for 12 weeks. Unlike the two larger rovers, Spirit and Opportunity, currently active on Mars, Sojourner could communicate only with the lander, not directly with Earth. Here is a link to more information.