A notebook cooler will help depending on the situation (I have a vantec lapcool). Dont expect cooler temperates while playing a game, your MBP will get taxed and little fans pushing room air can only do so much. It is however really helpful in getting your laptop cooler quickly after heavy usage.
Fongman: Like steelfist said, its not really a cooler. But it does elevate it a tad and Im sure the thing absorbs heat away. 🙂