NASA says in a statement, "Enceladus now appears likely to have all three of the ingredients scientists think life needs: liquid water, a source of energy (like sunlight or chemical energy), and the right chemical ingredients (like carbon, hydrogen, nitrogen, oxygen). Cassini is not able to detect life, and has found no evidence that Enceladus is inhabited. But if life is there, that means life is probably common throughout the cosmos; if life has not evolved there, it would suggest life is probably more complicated or unlikely than we have thought."
This is beyond exciting news. It's not going to be easy to send a probe that will be able to reliably search for life 750 million miles from earth, but neither is anything else NASA has achieved. It's looking more and more like we will have opportunities to discover extra-terrestrial life in our lifetimes if we choose to put our funding in these areas.