Yes, there was an App for that!
The Food Truck Tracker App by Burger Beast launched on Friday August 26th, 2011 to the largest Food Truck Event in Florida at that time. With over 50 Trucks from South Florida, Orlando & Tampa and 8000 fans in attendance it was a massive celebration of all things Food Truck.
Unfortunately the App which existed for iPhone and Android does exist any longer.
Below you can check out some screen shots of what the iPhone version looked like: