So you can now download multiple map areas when your at home on WiFi before you go out and they stay there so you dont need data to use maps.
Just do the following:
1. Make sure you have the latest version 5.7
2. When in Google Maps, press menu
3. Then choose: more > labs > and select "Download Map Area"
4. Go back to the map and center where you want to download.
5. Hold down your finger in the center of the map untill the address pops up.
6. Press the address bubble and the standard menu will popup only now you can select "Download Map Area" which will download 10sq Miles of map around that address, you can keep doing it until you have the whole of NZ if you want, its awesum!
Try it out, works great.
Orginal post from Google