Australia is well mapped. Even in the most remote areas it is likely there have been mineral survey groups through.
The Australian government mapping agency is called Auslig, and can be visited at www.auslig.gov.au Auslig have the entire of Australia covered on 1-250,000 maps, and these can be purchased on a set of CD Roms.

If you have a laptop and a GPS, consider using a moving map program. We recommend Ozi Explorer, programmed and coded in Australia by Des Newman of Queensland. The program is available for download at http://www.oziexplorer.com By loading this program into your laptop, and calibrating any map either from Rom or scanner, and then hooking it up to a GPS, the program will give you a moving map.

For regular Outback travel, the Westprint series are invaluable. Westprint's heritage maps give detailed information on the history of the areas you are traveling through as well as distances.