As posted by *rik*
http://www.myspace.com/darkcrimes

There are five main elements of a properly formatted script

Scene Heading/Slugline
Action
Character Name
Dialogue
Parenthetical

Always use Courier 12-point font!

Left Margin is 1.5 inches (appx.15 spaces)

From Left Margin justified left tabs:
Character name is appx. 25 spaces
Parenthetical is appx. 21 spaces
Dialogue is appx. 15 spaces

Dialogue should not run longer than 3.5 inches.

Use an unjustified 1.0 right margin.

1.0 inch top and bottom

Sluglines or Scene Heading.

Written in capitals and containing three pieces of information: (1) Where; (2) Exactly where, and (3) when. (2) and (3) are separated by a space, a dash, followed by another space.

(1) can be INT. (interior) or EXT. (exterior); (2) is a short identification of the place; and (3) can be either DAY or NIGHT.

For example:

INT. AIRPORT - DAY

You can use more than one subject.

For example:

EXT. AIRPORT - TICKET COUNTER - DAY

or:

EXT. AIRPORT/TICKET COUNTER - DAY

You need a new slugline each time you change the place, and/or change the time.

Action, or Description

The screenplay’s visual elements, where we show what is taking place on the screen. Character descriptions, what they are doing, the places, and everything the audience will need to assimilate visually. And nothing else!