Nothing has the potential to change society quite like the discovery of alien life. Many Star Trek fans have dreamed about it their whole lives. There are two parallel endeavors underway in the scientific community that have a very real chance of detecting the existence of alien life within the very near future. One is SETI, the Search for Extraterrestrial Intelligence. The second is the NASA Kepler mission.
SETI is a fascinating group of projects that analyze radio data to look for unnatural signals. Many forms of SETI have existed over the years, gaining fame back in the 1970's with the detection of the "Wow!" signal. A radio signal fitting all the characteristics of an artificially created transmission originating from space, which remains unexplained to this day. Modern SETI research into alien life mainly piggybacks on the data collected from the giant Arecibo telescope in Puerto Rico. This data is processed by thousands of personal computers around the world through the BOINC distributed computing project. This provides an exciting opportunity for average folks to participate in the search for alien life. The SETI institute is working on building their own dedicated telescope, the Allen telescope array, using donated funds. This telescope will greatly increase the chances of finding alien life.
The NASA Kepler mission is a space telescope located outside of the Earth's orbit, at the point between the Earth and Sun where gravity is exactly canceled out. This allows the telescope to remain stationary (relatively, as it is still orbiting the sun with the Earth) as it stars at one giant field of stars. Kepler is the first, and only, telescope capable of detecting earth sized planets around other stars that could potential sustain alien life. Kepler will spend the next few years staring at ~100,000 stars to determine what percentage of them have planets, how many planets, and the size/temperature of those planets. While this wont directly lead to any alien contact, once an earth like planet is found, with a temperature capable of supporting liquid water, future instruments will be able to analyze the atmospheric contents to look for signs of industrial pollution (i.e. alien life). Lets hope the aliens are abusing their environment as much as humans are.
To date, the SETI community has not been able to re-detect the Wow! signal or any other signals of particular interest that could indicate alien life elsewhere in the universe. However, you must understand that piggy backing on the Arecibo telescope is not particularly efficient, as it points wherever it wants. Furthermore, the SETI group is only analyzing a very narrow band of the radio spectrum, hoping that aliens will actually be using those frequencies. Given a dedicated telescope and a wider frequency band, the SETI institute could still see some very interesting signals.
The Kepler space telescope has been operating for about two years, and has so far produced astounding results. According to recently released data, from May to September of 2009, Kepler discovered 1235 planets around other stars, 54 of which have the right temperature to support liquid water and alien life. Of those 54, 6 are roughly the size of Earth. So in just 5 months, Kepler found 6 potentially Earth like planets around other stars. The Kepler mission is set to continue for at least 3 full years, so who knows how many other Earth like planets will be discovered in that time.
Going forward, my hope is that the SETI team and the Kepler team figure out a way to work together in the search for alien life. Future telescopes will be able to measure the atmospheric chemistry of detected Earth-like planets, looking for water, oxygen, etc., thus determining if human life could survive on the surface. Once the Allen telescope array comes online, it would be great if they pointed it at one of those Earth like planets rather than randomly sweeping through the sky (like they are today). Once focused on a specific planet, a much wider frequency range could be examined for alien signals. This is an incredibly exciting time in Astrophysics. The next few years could very well end up radically altering our view of humanity's place in the universe.