Marv Balousek writes that Northwest may add some non stop flights from Madison (to destinations other than their fortress hubs in Detroit, Minneapolis and Memphis):

Northwest’s Jim Cron said the growing popularity of regional jets also could inspire a competitor to begin offering more nonstop flights from Madison. He said leisure destinations like Florida and Las Vegas might be the most successful.
Brad Livingston, Dane County Regional Airport director, said he plans to meet next month with airline scheduling officials, including Northwest, to talk about improving service to Madison. He said the number of Dane County Airport passengers rose 13.6 percent in April over March and is 6 percent higher this year than in 2003.

I would be very surprised if they did this. The only reason they’ve added non stop flights in Milwaukee is to kill off Midwest airlines. Like other major airlines, once the competition is gone, we’re back to connecting via the fortress hubs.
On the other hand, this is possibly good news. However, the announcement smells like a request for local airline subsidies. I still think the best approach for MSN is to do everything possible to bring Southwest to town.
UPDATE: Northwest doesn’t like Wisconsin’s tax subsidies for Midwest Airlines and Air Wisconsin (I don’t either). Keep in mind that NWA has benefited greatly from Minnesota subsidies.