I am fairly certain ailen life is out there, however for them to reach here they would have to have master faster than light travel, which may or may not be possible. It is possible that they are struggling with this and reside in a different galaxy then we do.
If they exist, one would assume they would be emitting all sorts of EM radiation, but there isn't anything out there really doing that. So either the intelligent life is much much more advanced then we are and has figured out other means of communication, or they are much much less advanced then we are and there is no chance of contact as of yet.
The universe is also massive, so its possible that intelligent life exists somewhere right now, but the light/EM radiation has not yet even reached earth, and may not do so for tens of thousands of years.
RE: Why Haven't We Ran Into Alien Lifeforms Yet?