Google Maps Offline Mode for Android
In the latest version of Google Maps for Android you can now download large areas to use offline without WiFi or mobile/cell reception but can use the internal GPS to locate your position. In this version Google Maps for Android you can save 6 large areas dependent on internal/SD card memory available.
To obtain an area of interest when online, you need to navigate to the area you want to download and select 'Make available offline' from the menu. You are now shown the size of the data to download so you know how much space it will take up on your phone or tablet.