Google Maps (5.7) for Android now supports offline mode. This feature is called Download map area. You can select and download a selected are of 10-mile radius to your Android phone. It also allows you to download multiple map areas to your phone.
Download seems very fast on WiFi and fast in 3G network speed. I downloaded 4 different map areas and it work great. It download only map and not the satellite images.
How to enable Google map area in your phone ?
2) Open options menu
3) Select More
4) Goto Labs
5) Enable Download map area
3) Select Download map area.
2) Select More
3) Select Cache Settings
4) Select Downloaded map areas
5) You can see all the downloaded maps.
6) Here you can delete any number of downloaded maps