It's called Augmented Driving and it's by a company named imaGinyze. You probably ask yourself how can it work with the iPhone having no support for video analysis. The solution imaGinyze came up with was taking six to twelve pictures a second.
Unfortunately, it has many restrictions (see their Q&A section), and it's not even on the appstore. Nevertheless, it's very cool, and if they could figure out how to use an iPhone to help me with parallel parking, I'll be their first customer.
More details at Thomas who broke the news yesterday.