This picture shows where Phoenix is supposed to land on Mars. The almost-square area marked with a "D" is the planned landing site for Phoenix. The colors on this picture show how high the land is. Red and yellow areas are highest. Blue areas are lower. Phoenix is supposed to land on the low plains called "Vastitas Borealis" near the North Pole.
Image courtesy of NASA/JPL-Caltech/Washington Univ. St. Louis/Univ. of Arizona.