If you're like me you've thought about taking a portable GPS with you to Europe, but the cost of the maps for that region were discouraging.
I've found a source for free, open source maps that can be loaded to a Garmin GPS and are fully routable (I.e., you enter the destination and it provides turn-by-turn directions).
Follow the instructions from this website, with the exception that you should select "Generic Routable" as the map type rather than "Routable Bicycle" (the instructions provided are for loading maps to a bicycle GPS). This week I downloaded maps for Ireland and the map file easily fit onto an old 256 MB SD card that I had lying around.