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
screenwriting
screenplay
formatting
terms
film
structure
presentation
writing
business
software
TV
WGA
Final Draft
length
characters
guild
credits
union
FDR
FDX
scene headings
dramatic theory
outlines
adaptations
arbitration
producers
highland
pdf
fountain
guru
Celtx
managers
Movie Magic
awards
agents
rights
pitching
directors
iPad
iPhone
festival
short film
prelap