Next missions to Mars to include two different landers. Launched around the next opposition.

The landers will be rovers (there will be no "home base") and will land using the pathfinder airbag system.

http://mpfwww.jpl.nasa.gov/missions/future/2003.html

Also Mars Express.
http://mpfwww.jpl.nasa.gov/missions/future/express.html