This is bit out of the common topics on this site, but once it’s done it has to shared?
I’m happy to test the iPhone for a while and find out the GPS pretty useful. Because the iPhone use Google maps you have to download the current map tiles on the way and it cost money. I’m the type who always tries to find the way how to customize things for him self …bla bla bla.
Here is the cheap solution.
Luckily the iPhone is on the market for a while and people have same needs. If you have your iPhone Jailbroken the go to Cydia (freeware) and download OfflineMaps (freeware).
The tricky part is that you have to make the map for your self first and then upload it to you iPhone ;) You can either use the GMDL (freeware) application and make the maps of you desired location or you can download (207MB) mine I have made for my self. I made two maps, one in high resolution for Prague and one for whole Czech republic in lower resolution.. the map is not totally complete it lacks the lower part of Czech Republic, the one that touches the Slovak republic, but if you live in the same suburb as I do, this map will be fine for you ;)
The use the DiskAid app, (freeware) plug the iPhone to your PC with Windows (sorry guys but just for now) and navigate to /var/mobile/media/maps place the content of this file there. So that the Maps folder will includes two folders cz & ph, each of them with two files com.apple.Maps.plist & MapTiles.sqlitedb. Go to Your OfflineMaps chose those maps and you are done. Enjoy.
The GPS localisation system works without the Wifi, Edge, cellular data connection, so if not less you always find your self on the map and then you will know where you are.