Unless I need it, I usually don't carry my iPhone with me when I travel out of country. The charges associated with data and long distance calls are outrageous. I've used the GPS map feature on my iPhone to find my way around a new city, but at a huge cost.
Thanks to Dubbele's Mobile Street Maps, you can now pre-download an entire map of a place you will be traveling to. It works where Google Maps isn't accessible, or when you have data turned off (Flight mode) on your iPhone. Even without internet access you can still search for locations. The Dutch company has applications for a huge number of cities, over 400 to date. Some are free apps and some cost up to $2. It will pay for itself every trip, and once you've downloaded it once, it's on your iPhone until you delete it!
You won't have the GPS location of where you are but using these maps will help you get around without the worry of paying extra for the data.