Got an ANDROID phone?
 

then you might want to go to the market and look for two free apps:

Navfree navigation app using offline maps (OSM maps)

Skobbler using both on and offline maps (OSM ) Nice night more on this. and voice nav

no connection etc
Maybe useful for someone

check out out Andozic - uses Oziexplorer and Hema maps as well as others. I am quite happy with it, but phone needs to be connected to power supply.

:taz