Explore the Planet Mars:Realistic, interactive, 3D walk-though of a Mars base designed for the first humans to land on Mars including a Mars habitat, greenhouse, Mars car and robot rovers.
Clickworkers: Project helping NASA to date Martian land areas by counting craters. Information on how to participate.
JPL Mars Exploration Program: Various sections: Extreme Planet, Follow the Water, Mars Rocks, Life on Mars?, The Martian Mystique and Just for Kids.
Mission to Mars IPRO: Reports on a project undertaken to design and plan a manned mission to Mars utilizing existing space technology and off the shelf components. Interdisciplinary effort by students from the Illinois Institute of Technology and the Chicago-Kent College of Law.
NASA Center for Mars Exploration: Various resources on Mars Exploration with an educational emphasis.
Polar Landing Site for a First Mars Expedition: Discusses the reasons why a site on the Martian pole might be the best place to land a first expedition to Mars.
Romance to Reality: moon & Mars expedition & settlement plans
Russian Mars 96 Mission: Detailed description of failed Mars exploratory mission