iExit is a free app for iPhones and iPads that will tell you what's coming up at the next highway exit. This can be incredibly useful if you need fuel, food, a hotel, a bathroom or if you just need to go shopping. iExit will keep track of your location via your GPS device.
iExit's Search is powerful and dead simple. Search the next 100 exits for businesses (like Starbucks, Cracker Barrel, or KOA Campgrounds), amenities (like WiFi, Playground, or Truck Parking), rest stops, hotel deals, and much much more.
Additional resources for iExit Interstate Exit Guide for iOS