I think powerpoint is too dumb for this - you can view notes on one monitor and the pres full screen on another, but as you move through slides in the full screen, the other does not follow - it just stays on whatever slide you had shown in that view. You would have to advance the slides in both views simultaneously to do what you want to do - hardly the thing you want to do while speaking!
Dual monitor or not, this whole thing is lousy. Of course you could print your notes, but isn't the point to use the computer and not fumble with both the computer and a pile of paper?