A screenplay or script is a blueprint, written by a screenwriter, for a film or television program. Screenplays can be original works or adaptations from existing works such as novels. A screenplay differs from a script in that it is more specifically targeted at the visual, narrative arts, such as film and television, whereas a script can involve a blueprint of "what happens" in a comic, an advertisement, a theatrical play and other "blueprinted" creations.

The major components of a screenplay are action and dialogue, with the "action" being "what we see happening" and "dialogue" being "what the characters say". The characters, when first introduced in the screenplay, may also be described visually.



Got that from Wiki for ya. =)