A couple of years ago my friend Mohan turned me on to the novel "Daemon" by Daniel Suarez which I thoroughly enjoyed. It and it's sequel "Freedom" are a tale of what sort of changes, good and bad, could be forced upon us by the software around us. While certainly there were a couple of exaggerated technologies, by and large I am convinced that it is a fairly realistic possibility. Entertaining and educational.
Today I heard a podcast of the author speaking at one of my favorite lecture venues, the Long Now Foundation about the same subject matter. I recommend checking it out. Link