I expect that the only life we will ever find are microbes in our own solar system... dormant microbes at that. Mathematicians are increasingly warning that the number of variables (upwards of 200 at this point) that must be absolutely spot on for life to exist on earth are not likely (as in "virtually impossible") to exist anywhere else. Even if there are a billions planets in the "habitable zone". The odds are so against it happening on earth that it is becoming more likely that we are simply a computer simulation in someone else's universe, or that we live in a created world.
One example of this came out a few weeks ago... that dual gas giants like Jupiter and Saturn are EXTREMELY far out and permitted relative peace-from-bombardment for the inner four planets (and still do). (see March 23 in Proceedings of the National Academy of Sciences. ) This is just one MORE variable that allowed life on earth... and there are now hundreds of variables. And all of those variables simply go to set up conditions for life... the actual development of life poses a whole new set of fantastic against-the-odds variables that must be overcome.
Its possible that microbes get passed around like the common cold in the solar system. That is not what I consider "alien life". Further, lets assume that the earth "blew up" and sent shards off into space at the highest speed of a comet.. about a million miles an hour. It would still take about a million years to get to the closest uninhabitable planet. A piece actually getting to another planet, with microbes intact, surviving reentry and seeding another planet is probably about as likely as a gamma ray burst from a far-flung star.
The more we know, the more we know that it is less and less and less likely that their is other life in the universe. Earth is an anomaly, and the mathematics involved are slowing proving that.