Just about every overlander planning a trip has the use of a smartphone, a tablet or a multimedia device like an iPod Touch. The usefulness of the device does often depend on an internet connection and with data plans available in every country, it is worth taking a phone along that is unlocked and open to any GSM network.
Having a useful app on the phone makes it even more worthwhile... here are a few that I use and have found useful - Road Trip, TapaTalk, Offline Maps and the generic GPS app: