Trip Advisor has become the world's most popular hotel review travel site on the Internet. The Trip Advisor app (Android | iOS) (Free) makes it much easier to access Trip Advisor's hotel and restaurant reviews while traveling than using your smartphone's web browser. When using this app you must take the same precautions as when using Trip Advisor's website - the Trip Advisor "Popularity Rating" - you must rate the written opinions of the reviewers before deciding on a hotel or restaurant.
Look for reviews from travelers who share similar likes, interests and are located near you. Look for reviews that provide concrete examples of why travelers liked or disliked a hotel.
Traveling internationally? XE Currency Pro (Android | iOS) ($1.99) is simply the best currency converter app available. There is a free version of the app which displays 10 simultaneous currencies, while the pro version displays 20. The pro version eliminates the pesky advertising and is worth the $1.99.
The app automatically retrieves daily exchange rates for 180-plus of the world's currencies and precious metals. It lets you calculate exact equivalents of your home currency through its exchange calculator. It's accurate and extremely easy to use.
This app is absolutely invaluable while shopping, so you'll know what you're actually paying in your home currency, before you make your purchases.
The TripIt app (Android | iOS) (Free) lets you fully edit your itineraries, and add new plans to them while traveling. (The Pro version, has an annual subscription costing $49 per year.) One of the best features of TripIt is its ability to automatically add reservations you've made online by forwarding your confirmation emails to TripIt, instead of having to manually add the information. TripIt makes it easy to share travel plans with family and friends. Coupled with the "Pro" subscription, the app will receive travel alerts, such as flight changes and delays, and track most reward program memberships.
Open Table's restaurant reservation system and guides have become one of the top guides for home and travel. Open Table (Android | iOS) (Free) is currently the premier restaurant app for cities in the US, though there are up and coming app/Internet sites which bear watching such as CityEats (app currently available on iPhone only).
With the OpenTable app you can easily make restaurant reservations in the US and some other countries.
TravelTracker Pro (iOS only) ($9.99) is both a great stand-alone app and can import TripIt itinerary data. The app is an all-inclusive personal travel assistant. It will store all essential information for your trips, including every kind of reservation or scheduled event imaginable. TravelTracker includes live flight status, and can display live flight map tracking for US flights.
TravelTracker is a great complementary app to TripIt since it integrates TripIt data via its automatic import ability.
FlightTrack Pro (Android | iOS) ($9.99) is the ultimate flight tracking app for smartphones. With this app you can get push alerts, real-time flight itinerary updates, weather forecasts at departure and arrival airports, and live flight status with live flight map tracking.
Like TravelTrackerPro, FlightTrackPro is fully integrated with TripIt and is therefore a great complementary app.
iFly Pro gives you terminal maps, US airport status, a list of the airports' restaurants, cafes and stores with terminal locations, Wifi coverage, terminal services (ATMs, business centers, etc.), ground transportation information and more.
Reviews of these apps provided by Ned Levi, Consumer Traveler