If you have a GPS unit then you've got to download Maemo Mapper. It's the Nokia 770/800 killer app. But you've got to read its help file! I downloaded it a few days ago and gave up straight away. It takes a little time to figure out. Right now it's downloading around 150MB of satellite imagery of the area I live in. This means it'll be able to track me pretty much wherever I go locally. Ever wondered what was over that high wall? Maemo Mapper's satellite imagery will tell you