Gadling has previously investigated how mobile devices are changing the way we travel, whether it's helping us navigate public transit, letting you make cheap phone calls abroad or showing us location-based maps of nearby restaurants, hotels and businesses. Now, an emerging mobile phone technology called augmented reality looks ready to bring this mobile experience to the "next level."

It works like this: you start up an application on your phone using a built-in accelerometer, GPS and camera. As the application scans the world around you, it recognizes what you see, providing images, web links and information depending on where and what you're looking at. Think of it almost like the real world was "clickable." You could be walking down the street, pass by a restaurant, and have a link pop-up with a menu and weekly specials. Or in the case of augmented reality applications like acrossair on the iPhone (shown above) it can help you figure out the location of the nearest subway or metro stop. Other applications, like Wikitude and the Dutch service Layar let you browse directories of ATM's, bars and hotels around you.

As with any cool new technology, there's sometimes a catch. At this point, augmented reality apps like acrossair, Layar and Wikitude are only available to users abroad in Europe, although the companies are all promising a launch for U.S. users later this year. You'll also need to have a supported phone - in this case either a device with Android or an iPhone 3GS to take advantage. Still, the coming of augmented reality offers a bright view of our travel future. Imagine taking a trip where we were free of our guidebooks, able to have information on transit, shopping, eating and sleeping at our fingertips when we wanted it and hidden from view when we didn't. It's a concept that is rapidly approaching reality, though still working out some kinks - don't throw out that map just yet.