Researchers at Harvard have developed a robot that flies like a..fly.  Using laser micro-machining techniques developed in house, and DARPA funding, the robo-fly was constructed from carbon fiber and polymer.  This iteration is 60 mg with a wingspan of 3 cm and flies with a tether and external power – future versions are likely to be smaller, independent, and even more bug-like.  This technology will be ideal for gathering information from targets on the move, or where access might be difficult i.e. trying to plant a traditional listening device.  Once development costs come down and the technology improves, as it certainly will, one can imagine clouds of these things being released over hostile territory to engage in mobile, nearly invisible, real-time intelligence gathering.  Pretty difficult, in an Afghan cave for instance, to discern the DoD fly from its biological comrades.  They could be used to guide precision bombing as well, confirming targets on the fly, as it were.

Link: Technology Review: Robotic Insect Takes Off for the First Time:

By fitting many little carbon-polymer pieces together, the
researchers are able to create rather complicated parts that can bend
and rotate precisely as required. To make parts that will move in
response to electrical signals, the researchers incorporate
electroactive polymers, which change shape when exposed to voltage. The
entire fabrication process will be outlined in a paper appearing in an
upcoming edition of the Journal of Mechanical Design.

After more than seven years of work studying flight dynamics and
improving various parts, Wood’s fly finally took off this spring. "When
I got the fly to take off, I was literally jumping up and down in the
lab," he says.

Other researchers have built robots that mimic insects, but this is
the first two-winged robot built on such a small scale that can take
off using the same motions as a real fly. The dynamics of such flight
are very complicated and have been studied for years by researchers
such as Ron Fearing,
Wood’s former PhD advisor at the University of California, Berkeley.
Fearing, who is building his own robotic insects, says that he was very
impressed with the fact that Wood’s insect can fly: "It is certainly a
major breakthrough." But Fearing says that it is the first of many
challenges in building a practical fly…

…Tiny, lightweight sensors need to be integrated as well. Chemical
sensors could be used, for example, to detect toxic substances in
hazardous areas so that people can go into the area with the
appropriate safety gear. Wood and his colleagues will also need to
develop software routines for the fly so that it will be able to avoid
obstacles.