Screenwriting Guide
You don't have to spend a lot of money to write a great screenplay.
Before you can even think about writing a screenplay, you need to know the format. Personally, I use Scriptware and Final Draft, but if you're not going to write scripts ALL THE TIME, spending a couple hundred bucks on a screenwriting suite is probably counter-intuitive. There are a lot of free and shareware options, but sometimes, the easiest way to get from here to there is to just learn the basics.
And there are some things screenwriting software won't do for you- it doesn't know how to format a breakout. It won't capitalize the first appearance of a character in the script. It won't capitalize sounds; it won't tell you how to create a montage. Learning the basics makes it even easier to use advanced software, because you know all the tricks it doesn't.
Here's my basic guide (along with screenwriting advice) for creating an industry-standard screenplay. It's free, feel free to save it, copy and paste it, share it, e-mail it, repost it, what have you. Just remember that the most important thing in a screenplay is consistency. As long as you are consistent in the way you note things, a script can be an incredibly flexible document.
PDF | Word | TXT
Download a Sample Script (PDF)
Screenwriting Software Options
Pay for Play
Scriptware
Final Draft
Freeware, Shareware, and Open Source
Plot Bot
Zhura
Scripped
Celtx
BBC ScriptSmart