Electrons move by jumping from one atom's orbit to another and so on along a long line of atoms. This happens fairly regularly because electrons do it naturally but the trick to creating current is to get them to all go in one direction along the wire.

Substances are classified into three groups based on how easily electrons move around in them. These catagories aren't elcusive and many substances fall in between groups.

Think of this as a road. An insulator is a road obstructed by many tons of other cars (atoms) which refuse to let the electrons pass. A conductor is a material which allows the electron to pass as if he (the electron) had a lane all to himself.

Superconductors are special materials which allow electrons to move at a very quick rate throughout the material. Superconductivity is usually achieved by lowering the temperature of the substance so that the protons aren't moving as rapidly (remember heat equals motion) and this allows the electrons to find a stable path to travel along. Imagine it this way - is it easier to walk among a crowd of people who are running around randomly or a crowd of people frozen in place?.