A new model uses the lack of cracks on Pluto's icy region as supportive evidence that Pluto may have liquid subsurface oceans, raising the possibility of the existence of basic, microbial life in the Kuiper Belt (though it is only a very slight possibility).
more on the link
http://futurism.com/new-research-provides-evidence-that-pluto-has-liquid-oceans/
Europa has the best chance of having subsurface life, due to the heat generated by the gravitational forces at work there IMO.
