I have to say what Aborted say.
The chances of us being alone in the universe, which is what we call a limitless area of "space", it's constantly expanding at a rate that we would never be able to catch up with, so if not a single species in the universe lives on another planet than this one, I'd be fucking surprised.
Of course there's life on other planets and "aliens", it not being so would be retarded.. or religious, but I guess that's a synonymous thing.