Here's an excellent article on The New Atlantis web site about the history and evolution of military robotics. The emphasis of the article is on the rapid advances in robotics in the past few years, and their role in counterinsurgency warfare.
"When U.S. forces went into Iraq, the original invasion had no robotic systems on the ground. By the end of 2004, there were 150 robots on the ground in Iraq; a year later there were 2,400; by the end of 2008, there were about 12,000 robots of nearly two dozen varieties operating on the ground in Iraq. As one retired Army officer put it, the "Army of the Grand Robotic" is taking shape."
Another interesting tidbit ...
"iRobot, was founded in 1990 by three M.I.T. computer geeks; it is best known for the Roomba, the disc-shaped automatic vacuum cleaner that the company released in 2002. Roomba actually evolved from Fetch, a robot that the company designed in 1997 for the U.S. Air Force. Fetch cleaned up cluster bomblets from airfields; Roomba cleans up dust bunnies under sofas."