There's no special engineering going on here, just an Android app and an extreme case of cleverness.
If you own a Samsung Galaxy S, you can download Samsung's custom Android app called Road SMS. It's a simple text messaging program, but instead of the dull metallic backdrop of your average mobile OS, Road SMS pipes a live video feed from the rear of the phone behind the UI.
In other words, the phone simulates a window rather than providing a mere screen. Yes, it probably burns the heck out of your battery. But in a world we've cropped to a series of 3.5-inch screens, there are worse fates than getting a piece of our environment back. [Android Community via SlashGear]