A totally free iPhone GPS app--but is it any good?

Navfree USA costs absolutely nothing, and it might just get you where you're going--but don't expect a lot of bells or whistles.

Navfree USA is the only free GPS app to offer real turn-by-turn navigation. But it's not quite ready for the real world.

Navfree USA for iPhone offers turn-by-turn navigation, voice guidance, integrated Google search, and map updates for life--all for free.

How is that possible, especially when competing apps from the likes of CoPilot, Navigon, and TomTom sell for upward of $50?

The key lies in OpenStreetMap, Navfree's user-built, open-source mapping system. Because OSM map data is free to use, developer Geolife is able to offer the app free of charge (though in-app upgrades will arrive in 2011, and they'll cost you).

As you might expect, this is Navfree's blessing and its curse. The map data is only as complete and reliable as the users who supply it--meaning you might discover missing and/or inaccurate maps.

I took Navfree for a test-drive today, and the results were mixed. For starters, the app's POI database didn't seem to work at all. Although it showed lots of categories, each one was empty--and searches turned up nothing.

Address searches were slow and frequently incorrect. Very often the app couldn't find a house number, even one that's been around for decades. It didn't even list my city. And I found no way to pick an address from my own address book.

Problems like those suggest a pretty useless navigation app, but Navfree did do a respectable job navigating me to a nearby car dealership--after I looked it up using the built-in Google search.

What's more, Navfree looks pretty, runs smoothly while navigating, and keeps its interface simple. The voice prompts worked well, even if they did lack street names.

Ultimately, I'd say Navfree has potential--but for now I wouldn't rely on it for any important navigation. The latest versions of Magellan and MobileNavigator are downright stellar, and worth paying for. That said, maybe Navfree will help drive their prices down a bit.