They're going to go, at first, with celebrity guest hosts to maintain the numbers through the November Nielsen sweeps. Jerry Seinfeld, who definitely doesn't need ANY steady job on or off the air, is going to be the first, starting IIRC a week from Monday. You'll probably see more stunting with big name guest hosts through the holidays before it gets really serious--and they'll probably audition two or three before announcing a "winner" by the start of February sweeps. I doubt they'll let it go all the way to the May Nielsens, though they could if their #! candidate isn't available until then...