I came across two articles in the 23 Jan 2010 issue of the magazine "New Scientist" which caught my attention. Volume 205 No. 2744.
The first article, written by Stephen Battersby, suggests that we should be transmitting the fact of our existence to the Universe, in case everybody else out there is simply listening.The article goes on to discuss what the content of such a transmission should be. (pp28-31.)
The second article also by Battersby, "Meet the neighbours" (pp31-33) considers what intelligent aliens would look like. "Barring the appearance of flying saucers, there are two broad possibilities: either we have a close encounter with our neighbours by visiting the planets and moons next door, or we make an interstellar phone call."
"Putting it all together, the daring astrobiologist might be prepared to make a very small bet that ETI-type aliens will be social multicellular predators with eyes, sexes and sticky-out bits of some sort."