The Planetary Society will be sending along an experiment aboard
the Russian Phobos-Grunt mission, set for launch in 2009. The
probe will be the first spacecraft to land on the largest Martian
moon (assuming Phobos 2 did not crash into it after losing contact
with controllers in 1989) and return samples of its surface to Earth.

Onboard is an experiment acronymed LIFE for Living Interplanetary
Flight Experiment. A variety of microbes will be placed inside the
canister to see if they can survive the 34-month journey through
deep space to Mars and back.

To quote:

“The journey will be a test of one aspect of the “transpermia” hypothesis –- the possibility that life can travel from planet to planet inside rocks blasted off one planetary surface by impact, to land on another planetary surface. For example, if a rock on Earth contained life and were blasted off Earth, could it survive until it reached Mars? Or, if life existed on Mars, could it have been transported to Earth? The Planetary Society experiment will test the ability of life to survive the interplanetary voyage by flying organisms for several years through interplanetary space in a simulated meteoroid.”

More information may be found here:

http://www.planetary.org/programs/projects/life/