This is from my syllabus written years ago. For the most part it's passe now because of the proliferation of scriptwriting software. But I did recently get a question about margins recently so I'm pasting this page here for those who need the information.
Mark
FORMAT TERMS
FADE IN: (all scripts start this way – ONLY used in the beginning of a script)
FADE OUT: (all scripts end this way – ONLY used at the end of a script)
SLUGLINE / SCENE HEADING (three parts)
(1). (2) - (3)
(1) EXT./INT. (exterior or interior -- nothing else)
(2) SELBY'S LIVING ROOM (a basic location -- be consistent – keep short)
(3) DAY/NIGHT (that's all you use, don't get creative and punch in SUNSET, DAWN, TWILIGHT, etc.)
NARRATIVE
The action. Don't get overly descriptive or prosaic. Clean and crisp. Scripts are always written in present tense, i.e. he runs, she walks, they call out, etc.
DIALOGUE
Center or tab out character names. The dialogue should fall between margins approximately 3" and 6" from the LEFT EDGE of the paper. Don't ever break dialogue at a page end unless you put the character name on the top of the next page and the word (cont) next to the character name.
PARENTHETICALS
Brief directions centered under the character name. Keep your parentheticals short and sweet. Use narrative, not parentheticals, to provide any detail on what’s happening in the action.
SPECIFIC PARENTHETICALS
(beat) means pause. DO NOT put this in the middle of a dialogue sentence. Follow the screenwriting sample and center it below breaks in the dialogue.
(o.s.) off screen -- use when a character is in another room or out of direct view and is talking.
(filtered) -- use when dialogue is coming from an audio speaker like in a cop car, a radio/television, overhead speaker, computer, etc.
(v.o.) voice over -- this is dialogue that is narrated while something is shown like in documentaries or some film noir-type detective films. Blade Runner (not the director's cut), made use of a lot of voice over to explain the story after audiences found it confusing.
CAPITALIZATION
Capitalize CHARACTER NAMES in narrative the first time the characters are introduced. This includes generic characters such as COP, STUDENT, DOG, etc.
Capitalize SOUND EFFECTS such as BANG, SLAMS, SCREECHES, SIREN, RINGS, etc.
You can use capitalization for EMPHASIS such as:
Mark SLIPS his HAND into the woman's purse and pulls out a WALLET. She SPINS, SLAPS him and calls a cop.
MARGINS
My page format is set to the following: 1.3" left margin. 1.0" right margin. 1.0" top and 1.0" bottom margin. Page numbers upper right corner.
TITLE SHEET
Ask me and I'll bring one in. I use a fairly simple one but these are pretty much left to your imagination. Basically you want the title, your name, address and phone number (or your agent's) somewhere on the thing. If they can't find you they can't give you that big check. Some people like to include copyright notices and WGAw notices -- that's okay too but not necessary.
FONT
Use Courier, that boring old typewriter font, or similar. Believe me, Hollywood is not impressed that your laser printer can generate 1,000,000 fonts in sixty-six flavors and colors -- they just want a clean copy with a font that they can read.
CAMERA DIRECTIONS / SHOTS
Don't use them beyond the few simple transitions CUT TO and DISSOLVE TO, and POV, ANGLE ON and CLOSE ON.
TOTAL LENGTH
Scripts are typically between 100-115 pages since one page approximates one minute of screen time. The longer the script the more it will cost so lower budget films will mostly run between 95-105 pages and rarely longer.
MISCELLANEOUS
You don't have to put CONTINUEDs at the bottom or top of the page.
DO NOT number your scenes -- that is for a shooting script after it's been production locked.