Today's Image of Mars comes from HiRISE shows one of many recent impact craters that have revealed ice just below the Martian surface. This particular crater is about 6m in diameter and located in Mars' northern hemisphere, though it doesn't lie as far north as most observed craters exposing ice. This implies that ice may lie just below the surface much further south than previously assumed. Scientists speculate that the crater formed between April 2004 and January 2010.
Ice just below the surface could be used by future manned missions to Mars as a source of water, helping to sustain the crews for a longer duration without requiring as much cargo leaving from Earth. The ice could also serve as an environment for extreme life on Mars, since most life requires some sort of water.
Clicking on this image will take you to the Space.com article about it.