[Capt.ArD]

If you read Michael Chrichton's PREY, he explains how such nanobots can "clone" themselves. Note, i am not using this example as fact, but it is a good theory.

In order to manufacture a robot that small, you would like to do it with tools that are also that small. start off making a tiny machine capable of producing more machines, only smaller. have those machines make more, smaller machines, which make smaller machines, which make your final product. now you have a whole bunch of nanobots, as well as a large number of nano-sized "machine tools" or "constuctor bots".

now, send the whole crew along on its excellent adventure. when it gets to its destination, the bots start their colonizing, while the constuctors start turning out more bots, and more constuctors. they can use the natural resouces of the planet for materials.

pure theory. alot of things that need to be worked out, and definitely not within our current capabilities. fun ideas though.