[Joel]

This is a very old AppleScript, so it may take some tweaking, but it will take a number of selected .graffle files in the Finder and export them to PDF:

tell application "Finder"
	repeat with theFile in selection as list
		my convert_to_pdf(theFile, "pdf")
	end repeat
end tell

on convert_to_pdf(graffleAlias, fileType)
	tell application "OmniGraffle Professional 5"
		open graffleAlias
		set rawPath to path of document 1 as string
	end tell
	searchReplace(rawPath, ".graffle", "")
	set rawPath to the result
	tell application "OmniGraffle Professional 5"
		set myPath to POSIX path of (rawPath & "." & fileType)
		--display dialog myPath
		save first document in myPath as fileType
		--close first document
	end tell
end convert_to_pdf

on searchReplace(theText, SearchString, ReplaceString)
	set OldDelims to AppleScript's text item delimiters
	set AppleScript's text item delimiters to SearchString
	set newText to text items of theText
	set AppleScript's text item delimiters to ReplaceString
	set newText to newText as text
	set AppleScript's text item delimiters to OldDelims
	return newText
end searchReplace

Hope it helps,