Must have travel apps

I always take my iPhone and my Android Asus Transformer Tablet with me when I go travelling.

Here are some of my must have travel apps:


Kayak
This is my must have. I have tried Tripit, Tripcase and many others, but I like this one the best. Completely free and very easy to use. It also can show you your flight status


Yelp
This is brilliant for finding out restaurant reviews


Tripadvisor
This is the most popular way to read reviews on attractions, hotels and restaurants. Brilliant app


Opentable
Make a restaurant booking with this app


Flightaware
Very useful for tracking your flight


Voxer
Great little app that lets you send your friends messages, photos and voice recordings even when they are offline


Viber
Great for making free calls over wifi, but you can't leave offline messages which is a shame


Foursquare
Not really a must have, but very useful. I use foursquare to check-in to places let my friends know where I am, unlock badges and sometimes offers for that business

All these apps are available on both the iPhone and on Android.