I'm convinced that there's life elsewhere in the universe. That thing is just too vast for earth being the only inhabited planet.
I am, however, not convinced that it's life as we know and defined it on earth. Most of the creatures that inhabit this planet, including mankind, mainly survive on O2 and H2O, but there have been bacteria found who thrive just as nicely on CH4 or other chemical compositions. I wouldn't be surprised if life existed on planets that don't have earthern (surface) conditions (like the composition of the atmosphere).
I can't say anything about their supposed intelligence, though. Intelligence is relative to begin with... What might be important in our society, might be redundant in theirs.