Plate Tectonics :]

The lithosphere ( the hard outer layer of the earth) is broken up into 8 major sections, called tectonic plates.These plate tectonic move in relation to one, by the plate boundaries. These three boudaries are called the divergent boundary, convergent boundary, and the transform boundary. ( see convergent and divergent boundaries for more :] )

There are many theories for Plate Tectonics. The theory encompasses the older concepts of continental drift. The theory is that the continents release earth's core, thus turning into the 7 continents, Africa, North America, South America, Australia, Antarctica, Europe and Asia.

The forces that cause the plates to move, are friction, gravity and external forces.

Here is a Video showing you the results from plate motions.
http://www.youtube.com/watch?v=2TVLUBRfHgM&feature=related