Hacienda71, I'm in a similar dilemma.....I'm off to Cherburg in a couple of weeks and I'd like to test my smartphone, HTC Desire. I figured out that I can download the maps of the area I want to visit through my wifi at home and use them with GPS while in France. GPS is free so no problem there..... but make sure you disable your data 3g and 4g if you have it while you are in france......
To pre download the google maps follow this procedure:
Run Google Maps
Press menu
Go to more
Select labs
enable "precache map area"
then
do a map search of the area you wish to download
The Map will be shown with the name..... press the arrowhead
Select precatch Map Area (last one in the list)
That will download around 10 miles around in all directions
if you need more maps just navigate to the area you wish to download and you know what to do next
Save your money and buy yourself a big memory card instead