A storyboard is group of illustrations displayed in sequence for the purpose of pre-visualizing a motion picture, or an animation. The storyboarding process, in the form it is known today, was developed at Walt Disney Productions during the early 1930s, after several years of similar processes being in use at Walt Disney and other animation studios. Below is a storyboard created for the most recent King Kong movie.

Below on the left are the original storyboard images from Alfred Hitchcock's "The Birds", on the right are the actual corresponding frames. 

Here is a selection of from the storyboard for Star Wars II

Below are several images from the 'North by Northwest' storyboard