Gmap v1.2 [AppStore]

This app didn't work very well in the past. Today has been updated up to version 1.2, which adds numerous bug fixes and real-time turn tracking. It does indeed provide turn-by-turn directions (distance countdown to each turn) by way of GPS. Local points of interest (Food, Fuel, etc.) can be found, addresses can be searched, routes can be edited, detours added, and types of roads can be avoided (highways, toll roads, etc.). If a turn is missed, the route is recalculated. By having actual maps stored on the device itself, it does not require the use of an active internet connection to pull mapping data (like Google Maps).

The 800-900 MB applications each cost $19.99 and carry regional maps for the Western and Eastern halves of the United States (Europe coming soon, some time in March).