This sort of story happens a lot these days.
I think the 'Sand Kings' story from... what was that series. Outer Limits 2?
Also there was a Next Generation story where Ensign Crusher did a class project involving some kind of nano bots.
I think Futurama did a spoof of this plot on a... robot sort of planet, was it?
'Dragon's Egg' is well worth reading, by the way.