Just as its name implies, OffMaps allows you to download maps to your iPhone for offline use, so you can find your way around without racking up international data usage charges. The app costs $1.99, but includes two Guide credits, for downloading city-specific travel listings and maps. International listings are somewhat limited at this time, but the app can still pay for itself in a day, considering how much you’ll save on data usage.

3. TripIt

After creating an account on TripIt.com, simply forward your flight, hotel, or rental car confirmation emails to plans@tripit.com, and essential travel details will be stored online. Use the iPhone app to access all your trip info on the go, including flight status info. All for free. Trip details are saved on your device, so you only need a data connection to synchronize updates.

To see what other apps Frommer’s recommends for travelers, check out the entire list here.