Celtx. It’s a free tool for creating a screenplay and offers robust collaboration and sharing options (and it’s for Mac, Linux, or Windows).

In addition to screenplays, it also supports AV scripts (documentaries, ads, music videos), audio plays (radio, podcasts), theatre (U.S. and International Standards, and plain old text). But if screenwriting is your game, there are many choices…

Dedicated Screenwriting Tools

Celtx (free, Beta) Mariner Montage ($139.95) DreamaScript ($195) Movie Outline ($199.95) Final Draft ($229) Movie Magic Screenwriter ($249.95)

Tools that can handle Screenwriting (to some degree)

Latte and Literature's Scrivener ($39.95) MacroMates TextMate: Try the screenwriting bundle ($63 for TextMate, free Bundle) Apple iWorks: Try the Screenplay template for Pages ($79 for iWorks, free template) NovaMind Platinum ($249)

I’m not a screenwriter, but I’ve dabbled in it. For this, I use Celtx. For my other varied textual needs, I rely on TextMate, Scrivener, iWorks(Pages), and Redlex Mellel. This is off-topic, but I just have to note that I especially love Mellel. But it’s not for screenwriting. It’s a versatile word processor. Why I love it and how I use it is a topic for another post, another day…