This is a mapping application which allows you to use a map anywhere you need it without having a data connection. It also has online routing and audible navigation.
The application is open source and the offline data is based on OpenStreetMap - the free wiki map (OSM). The "donation" version OsmAnd+ has experimental offline routing.
Highlights of the online mode:
- 14 different map layer sources from the Internet
- navigation (routing) with voice instructions
- search, edit POIs
- submit OSM bugs
Highlights of the offline mode:
- vector street map
- comprehensive search of addresses and places
- efficient storage format to fit big areas onto SD card
OsmAnd is still in active development. However the free version on Market will not be updated. Please consider "donation" version OsmAnd+ to support the project or co-fund a new feature which is important for you. You can always get free version of OsmAnd+ on osmand.googlecode.com (night-build).

See web site for details.

Screenshots: