My shop said mine comes on thursday, but I'm hoping they'll ring to say they have it before then...
A robot sim is like a creature. In sims2, every expansion pack had a new creature that could be made, or a sim could be turned into one. They often act quite like normal sims, and you can control them, though they often have some unique needs and abilities. In sims3, the controllable ghost was the creature in the base game, and the mummy was the creature for world adventures.