It is really annoying because in the outback you often do not have a 3g signal.
I tried 3 apps and only found one that was really any good
It seemed Pretty handy http://xgps.xwaves.net/index.php/Downloads
although you need to jailbreak your iphone and I didn’tn’t want to do this.
I have now uploaded an app that allows me to download maps onto my iphone via an iphone app called offmaps (it uses open source map info). What I didn’t like about this app was that it did not allow you to download non-urban areas of australia so not usefull for my purposes
This is my app of choice. It allows me to download huge maps anywhere for free. If I want a serach function I have to pay $1 for the pro version. The maps are open source and not quite as nice as google maps but pretty good