on open these_items
	repeat with i from 1 to the count of these_items
		set this_item to POSIX path of item i of these_items
		do shell script "touch " & "\"" & this_item & "\""
	end repeat
end open

on run
	display dialog "Drop a file on this applescript and it's modification date will be set to the current date and time." buttons {"Ok"} giving up after 10 default button 1
end run

open touch in the applescript editor