For the real computer literate, you can combine this with CVS to allow easy collaboration in writing a screenplay from multiple locations. In other words, someone in LA and someone in NY can each have copies of the text file and make their own changes. They synchronize their changes with a CVS server and their local copy is automatically updated to represent the changes that have been made by other people. Details of how to set this up are left up to you, but the flexibility is endless!
Coming Soon!: I intend to create a quick GUI to make this easier for those people not familiar with perl and the command line.