I've finished a roughly drawn storyboard of La Seduzione, which given my limited drawing skills is about the best I can do. I've also finished an early version of the animatic. (You can read other posts about the making of this animated short here.)
A storyboard is like what you see below... a visual interpretation of each scene in the movie. (Just to be really confusing, in animation we call shots scenes.) It's usually accompanied by a text description of what is going on. Click to enlarge:
Once the storyboard is finished, an animatic is made. This is essentially a filmed storyboard. The image of each scene is kept on screen for as long as it would appear in the final product. Scratch (by which we mean temporary) music, dialogue if any, and some sound effects accompany the images.
An animatic allows a filmmaker to preview the timing and story flow of the film before a big investment is made in animation. I know I will probably putter around with my animatic for weeks before I feel comfortable enough to start animating scenes.