Hey, everyone: I downloaded an app from the Apple app store called GunFreeZone. It uses your zip code to determine what locations are near you. So as you go into businesses, you can open up app and list whether the business is gun friendly or not. They're kind of relying on gun owners (and anti-gun hippies, I guess) to update their database. So every time you list a business as gun friendly or gun free, their database is updated. If enough gun owners download the app and start listing businesses, we can have a hand reference right on our phones.
Again, it's called GunFreeZone. It's available for both iPhone and Android devices. I've been using it for a couple of months now and it's really easy to use. Tap on a business and the app brings up an interface that shows an anti gun or pro gun icon and the apps asks you, 'You say?' You select an icon and the choice is saved to the database.