This is cool. Here's a hacked version of the official Google Maps/Navigator for Android phones that caches downloaded maps to the SD card so if you use it later with no data access the maps are already on your SD card. I tried it to work this morning by thumbing through the route at home so it would load the maps to my SD card and then putting my phone in airplane mode so I wasn't getting any data and it worked perfect on the drive. It is also hacked to use Google turn by turn Navigator internationally which apparently works great in China as other places. I tried it on some more popular third world destinations though and just get "no route found" when I ask for directions.

Make sure you enable map cache to SD Card under Menu -> More -> Brut Mod -> Save map to cache and Read map from cache. It is off by default.

Right now the map caching is a little primitive. You display a map and it is cached to your SD card meaning the best way is to before you leave thumb through the entire area of interest at a suitable zoom level to load the maps to SD. The author promises in the near future to make it compatible with a separate map downloader app so you can download maps for an area in advance with automation.

Download it here.

http://forum.xda-developers.com/showthread.php?t=630887

Find the link for the .apk file, copy it to your SD card in your phone and install from there. Obviously it is not Google approved and not available in Market. It coexists fine with the "real" Google maps so you can install it side by side without screwing up regular Google Maps/Navigator.

Hey that's a GREAT find. If you find something like this for the iPhone, you will make more than a couple of guys happy on this site.

I can make your I-Phone make and receive free phone calls over wifi or data anyplace in the world to or from from any US phone. Can't help you with the maps though.