Yes. As of August 2012, Final Draft Writer is available for iPad for $49.99.
FDX Reader by Quote-Unquote Apps can be used to read Final Draft 8 documents (.fdx files) on the iPad or iPhone, but is not a script editor.
Answer Index
script
scriptwriting
screenplay
screenwriting
formatting
terms
film
structure
presentation
business
writing
software
TV
WGA
Final Draft
length
guild
characters
credits
FDX
FDR
union
scene headings
dramatic theory
outlines
adaptations
arbitration
producers
fountain
highland
pdf
managers
Celtx
guru
Movie Magic
agents
rights
pitching
awards
short film
iPad
iPhone
festival
directors
musical