NOTE: This is for keynote 2, which is bundled with iWork '07. I've posted an updated script for keynote 3.
on run
display dialog "Drag keynote documents on me to convert to PDF."
end run
on open draggeditems
repeat with thisFile in draggeditems as list
tell application "Finder" to reveal item thisFile
set thisFile to thisFile as alias
tell application "Keynote" to open thisFile
tell application "System Events"
tell application process "Keynote"
set frontmost to true
if menu item "Hide Inspector" of menu 1 of menu bar item "View" of menu bar 1 exists then
keystroke "i" using {command down, option down}
end if
click menu item "Export…" of menu 1 of menu bar item "File" of menu bar 1
repeat until sheet 1 of window 1 exists
end repeat
tell sheet 1 of window 1
click radio button "PDF" of radio group 1
click button "Next…"
end tell
repeat until button "Export" of sheet 1 of window 1 exists
end repeat
tell sheet 1 of window 1
click button "Export"
end tell
delay 3
keystroke "w" using command down
end tell
end tell
end repeat
end open
