The immediate goals of the Phoenix mission are to study the geologic history of water, and to search for evidence that Mars may have sustained life. Continued research will be done to determine whether dormant organisms could come back to life.
We must now patiently wait for news of whether conditions on the red planet could have ever supported life. For complete coverage, visit NASA or Bad Astronomy. Of course, if Valentine Michael Smith is spotted, I'm all over this story... In the mean time, watch this inspiring video by Phil Plait as he describes why the lander's arrival image is his 'favorite picture of all time':