Garmin GPS 72

If there are any other owners of the above around here, you will know that it comes with a useless "marine" background map featuring only the capital cities and loads of lighthouses which we're unlikely to encounter much in our 4wds. Garmin only offer a horrendously expensive MapSource product with POIs of dubious interest.
The good news is that, even though the 72 is a non-mapping receiver, it is possible to use the one megabyte memory in the unit to upload your own background maps with user-defined POIs. After a good deal of research on the internet and some trial and error, I've finally managed to replace the built-in "map" with a quite detailed NSW Outback map featuring some 100 towns and destinations (Mungo NP, Hungerford Gate, Cameron Corner, Kallara Station etc). As the built-in memory of the unit can take much more, I am planning to refine this, adding such POIs as rural petrol stations, UHF repeater locations, and landmarks such as remote pubs (Silverton, Tilpa etc), aboriginal sites, and accommodation (motels, stations). Nor will NSW remain the limit, and adjacent areas in SA, VIC, and QLD will also be added gradually. The files should also work with other Garmin units.
If anyone wants detailed instructions how to do this (it involves downloading a couple of freeware programmes from the web), or a copy of the maps I use, just email me! (Any GPS data for good 4wd tracks in NSW would be very much appreciated in return...)
For the benefit of non-members, my email address is g dot minnerup at unsw dot edu dot au.