You have a story to tell. Use Final Draft to write it.
Use your creative energy to focus on the content; let Final Draft take care of the style. Final Draft is the number-one selling word processor specifically designed for writing movie scripts, television episodics and stage plays.
It combines powerful word processing with professional script formatting in one self-contained, easy-to-use package. There is no need to learn about script formatting rules, Final Draft automatically paginates and formats your script to industry standards as you write.
Final Draft Official Site
Read TXT file for installation instructions.
If you like the software and can afford it, buy it and support the developers.