At least as of this writing (1:45p PT) NBC confirms there will be a newtonight and that will be hosting.
Among the guests, Chuck's Zach Levi. Between all thenews and all the Chuck news lately, that's about as close as it gets to Jupiter aligning with Mars for me as far as late night TV goes. I'll be watching!
Tom Brokaw and Roseanne Cash are also scheduled to appear.