Yes. Celtx contains a screenwriting component, as does Five Sprockets.
In addition, some pay programs offer free demo versions with limitations, like a limited trial period or watermarked printing, for example.
Answer Index
script
scriptwriting
screenplay
screenwriting
formatting
terms
film
structure
presentation
writing
business
software
TV
WGA
Final Draft
characters
guild
length
credits
FDX
union
FDR
scene headings
outlines
dramatic theory
arbitration
adaptations
highland
pdf
fountain
producers
guru
Celtx
managers
Movie Magic
pitching
awards
rights
agents
directors
festival
iPhone
short film
iPad
musical