Newspapers across the country are in turmoil as advertising revenue continues to flood out of print and onto the Web. Classified advertisements, especially the real estate listings that papers have long depended on, have shifted to Craigslist and other free Web sites.

A new home-finder application for the iPhone that I wrote about this week could be something else for publishers to worry about. The Trulia.com iPhone app finds your location and then displays all available open houses and other listings on an interactive map. With a couple taps of the screen, you'll find details about the house, agent contact information, and photographs. Why carry around the bulky weekend newspaper when you can pull up real-time open house information for free while you're actually in the neighborhood where you want to buy?

Trulia CEO Pete Flint told me that the application will go "right at the heart" of newspaper real estate ad revenue.

"Unfortunately, this is another nail in the coffin of newspapers," Flint said.