There is little point in me trying to write a style guide since there's a really good one already online. Sure, it doesn't look like a typewriter, but it has a lot of great information on content, structure, format, and many other facets of playwrighting.

This is all available at The Playwrighting Seminars.

If you're interested in learning how to write a musical, you should check out The Stage Online.

Also, for those of you who use Word, this template (made by Scott Dai) is a great resource. To use this file, open it in Word and go to File/Save As. In the Save As Type box near the bottom of the dialog window, select "Document Template (*.dot)." The Save In box changes to a default "Templates." Click Ok. Now, when you go to File/New/General Templates, there is an option called Play.dot.

Then simply type CTRL+1 before typing a character name (the character saying the dialog), CTRL+2 before dialog, and CTRL+3 before a stage direction.

Just in case anyone wants to know about copyrights, there's some useful information here.