GPS for Droid 3 to be used in Europe

[floorlizard]

I will be visiting Europe next week and would like to use Google Maps while traveling around each of the cities. However, due to the cost of data while roaming overseas, I cannot do this. I have heard about some apps that will allow my Droid 3 to act like my car's GPS by using pre-loaded (downloaded) maps while connected to the GPS satellites. Thereby, saving me money from using "live" maps like Google Maps. Can anybody make some suggestions on what they have used and what works best? I would like to pre-load points-of-interest with addresses, etc. and route to these locations. Also, since I will not have a car, are there any apps that will route using public transport options / walking much like Google Maps? Thanks in advance for your help!