I'm currently watching the live feed and it looks like NASA is announcing the presence of water in the near surface of Mars -- namely in the form of saturated sediment (mud). They've seen evidence of water that boils off rapidly in the thin atmosphere of Mars during small avalanches in the mid-latitudes. They're talking about a handful of swimming pools of water in each event. This is the "Squirting Gun" for water on Mars.
There's also a serendipitous discovery of new dark spots on Mars which have appeared in the past few months. They look to be very recent impact event craters which allow us to see the subsurface details from Mars which haven't been eroded. In essence, you can go look from orbit at the geology of Mars without digging. The bad news is that ~12 big impacts happen per year and may be hazardous to astronauts on the surface.
http://www.nasa.gov/multimedia/podcasting/jpl-mgs-20061206.html
