I think that, considering the magnitude of the observable universe, and the relative ease with which life seems to have evolved on the Earth, it is probable that there is life elsewhere in the universe. But that leads to three other questions of interest.
1) Is the life intelligent?
Again, considering the number of stars and worlds there must be, I think it's likely.
2) Will we ever contact it?
This is much less likely. I'd still like to think so, but space is big, and so far, we've just barely been able to send a craft out of our own solar system. This is a big question mark for the present time.
3) Have aliens visited us on Earth?
Almost certainly not. There is no good evidence for this, and it seems that if we were being visited, we would know about it by now.