WorldMate (Apple iOS and Android, free)
This itinerary app keeps track of all your travel-related details: car rentals, hotel reservations, flight details and much, much more. Not good enough? WorldMate also converts currency, provides weather listings and can help you find a car or hotel rental in a pinch. Read much more about WorldMate and why we prefer it to TripIt in our head-to-head review of the two top itinerary apps.
GasBuddy (Apple iOS, Android, Windows Phone, BlackBerry, free)
The only thing worse than paying an arm and a leg for gas is running out of it completely. GasBuddy alleviates both of those concerns by using the power of crowd-sourcing to display all the gas stations near you, along with their current gas prices. Highly recommended, although the prices may be a bit off in less-populated areas.
Sit or Squat (Apple iOS and Android, free)
Sit or Squat is a hilariously named app brought to you by Charmin, the toilet paper provider. It has one purpose: to identify bathrooms around you and let you know if they're nice and clean . . . or not so nice. This app is crowd-sourced, too, but it receives mixed feedback from users. Still, it's helpful (and entertaining) in a pinch.
LocalEats (Apple iOS, $0.99)
When you're visiting another part of the country, diving into the delectable local cuisine beats eating out at a fast food joint you can find in every home town across America. The iOS-only LocalEats app highlights the best of the independently-owned restaurants in your vicinity, complete with menus, travel directions and a bevy of filters of help you quickly sift through the steakhouses and find the award-winning crab cakes your tummy's a-rumblin' for.
Yelp (Apple iOS, Android, Windows Phone, BlackBerry, free)
If you don't have an Apple device or don't want to limit your dietary choices to the best local restaurants, there's Yelp, the mobile version of the well-known ratings website. Actually, you'll probably want to pick up Yelp even if you have LocalEats, since it provides ratings for all kinds of services, including nightlife, spas, shopping, automotive repair shops and even dentists. It's incredibly handy if a fender bender breaks your bumper -- or your tooth.
EveryTrail (Apple iOS and Android, free)
Go take a hike! EveryTrail uses GPS to make a map of your wanderings, ensuring you'll never get lost. Helpful guides and trips uploaded by other users point you towards points of interest, and there are all kinds of trip stats and other helpful features. A $3.99 Pro version adds offline maps, removes the ads and lets you instantly sync your trips between the app and EveryTrail.com.
JiWire Wi-Fi Finder (Apple iOS and Android, free)
Paying for cellular data can get expensive on the road, especially in foreign countries. Wi-Fi Finder maintains a database of over 550,000 worldwide Wi-Fi hotspots and can point you towards nearby access points quickly. Be warned: the app shows a mix of free and paid Wi-Fi hotspots, though it clearly differentiates between the two. Even better, it works offline, so you can find your way to the Web even while disconnected.
Google Translate (Apple iOS and Android, free)
Speaking of foreign countries, Google Translate is a free, must-have app for world travelers. It translates 64 different languages and even provides out-loud voice reading for 40 of them. Google Translate pops out the occasional dialect error, but overall it's highly accurate and great for conversing with locals who speak other languages.