The end of a compass needle that points north was historically called the "north" magnetic pole of the needle. Since dipoles are vectors and align "head to tail" with each other to minimize their magnetic potential energy, the magnetic pole located near the geographic North Pole is actually the "south" pole.
The "north" and "south" poles of a magnet or a magnetic dipole are labelled similarly to north and south poles of a compass needle. Near the north pole of a bar or a cylinder magnet, the magnetic field vector is directed out of the magnet; near the south pole, into the magnet. This magnetic field continues inside the magnet (so there are no actual "poles" anywhere inside or outside of a magnet where the field stops or starts). Breaking a magnet in half does not separate the poles but produces two magnets with two poles each.
Earth's magnetic field is probably produced by electric currents in its liquid core.
Earth and Stars from NASA (all restriction free)
Magnets are based on a free Google Sketchup Model [link]
and heavily altered in CS3