After reading a few reviews of people on this site, I just bought the BestTravel offline map app for my iphone. (http://besttravelapp.org/) I can't for the life of me figure out the settings on my iphone that would enable me to turn off international roaming, yet leave the GPS on. In a nutshell I want to use my iphone as a navigation tool, ie use the "where am I" feature of the app, without incurring any charges. I've checked their site but can't for the life of me find any instructions on how to set things up. Does anyone have experience with this or any other offline mapping app and the settings that need to be set?