...you two may finally settle your argument over
whether parts of Mars subsurface are still 'wet'.
The 2009 Phoenix rover will carry a Russian neutron
-emitting experiment, capable of detecting light-elements
like hydrogen in martian soil down to a depth of a meter.

Of course, Robert, you will not find 'pure' liquid water
near the martian surface, not even in Hellas. At martian pressures
and temperature ranges, pure water would either flash freeze,
or on those rare 'warm' days [max: 0 - 10C] at high noon near the equator
of Mars, rapidly boil off.

As for you, Nick, I'm sticking with the idea that near-surface
highly saline, acidic slurries [a fluid, or semifluid at temperatures approaching 0C] may exist near the surface of the equatorial regions on Mars, at high noon.
Of course, we need ground truth to clinch the case, either proving or disproving the idea of hydrated fluids [muds, slurries, etc] existing today on Mars, and I think that the Russian neutron-emitting experiment on Phoenix,
plus complimentary close-up imagery, and mechanical manipulation [a robot-arm or wheels applying pressure on suspect material], etc., would be upto the job.

cheers.

Jacob