Listen in on cops, NASA for $0 with iScanner app (Sunday only)

There’s a particular subset of Americana that enjoys tuning into frequencies for law enforcement and emergency response units. Those with iPhones, iPod Touches or iPads know there plenty of apps that satisfy this penchant for real-life drama, like Police Scanner, Emergency Radio and 5-0 Radio. (Links launch iTunes.)

But if you want more than the inner workings of terrestrial agencies, how about being privy to the action inside NASA? The iScanner app offers both — along with 4,700+ feeds for police, fire, EMS and others across the United States. And for Sunday only, developer Fusion Mobile Solutions is giving its $0.99 app away for free.

The special promotion is in honor of the Shuttle Discovery’s much-anticipated landing on Monday. The shuttle will touch down at Cape Canaveral after 13 days in space, where it delivered a multi-purpose logistics module to the International Space Station.

The idea is that educators, students and enthusiasts will be able to tune in the day before, to experience the live chatter between the shuttle and mission control. In addition to this landing, users can also get the inside scoop on NASA’s future plans for new shuttles and missions — like space travel to Mars.

Think you already know the app? Not so fast — iScanner just went through a major update, with more feeds and police/emergency/dispatch codes, plus a facelift on the user interface. These changes could make it feel like new again.

If you like scanners and you like space missions, then be sure to snag iScanner for free (tomorrow only). And let us know if you like it!

(iTunes link to app)