tell application "Mail"
	(* Change MailTasks into the name of your calendar *)
	set theCalendar to "MailTasks"
	set theMessages to selection
	repeat with msg in theMessages
		set msgsubject to subject of msg
		set msgurl to "message://%3c" & (message id of msg) & "%3e"
		try
			tell application "iCal"
				set newTodo to (make new todo at end of todos of calendar theCalendar)
				tell newTodo
					set summary to msgsubject
					set url to msgurl
				end tell
			end tell
		end try
	end repeat
end tell