There's been a lot of talk lately about travel apps, with some people suggesting they're just a waste of money.
A travel app is not a guidebook, and at $.99 it's not meant to replace your $20.00 Lonely Planet or Rough Guide. Read those big volumes before you leave, and if you have room in your luggage take them to refer to before you start the day.
But once you're out and about, a good travel app should be all you need.
Here's what to look for when buying an app:
1. Offline Functionality
This is crucial if you're using an ipod touch of course, but also if you want to avoid roaming charges on your phone. You should be able to get the most use of your app offline. It should have multiple search categories, like churches, monuments, museums, etc, rather than just "what to see". This way you can find out about something you hadn't planned to see. For example, while wandering in Rome I came across many churches I hadn't read about previously. I was able to look them up in the app and get all the information I wanted.
2. A Legible Public Transport Map
Ideally, your app should include not only the map, but also directions on how to get from point A to point B using the public transport system. My London app was very good at this, even giving me several choices with the time of the trip and the number of transfers included.
3. A Searchable Street Map
One of the nice things about app maps is the ability to zoom in on where you are when you need the name of every little street, and to zoom out when you want to put your location in context. All this without looking like a tourist fumbling with a map or staring at a guidebook, a real advantage where tourists are targets.
4. Additional Online Functions
While you need to be able to use your app offline, one of the advantages an app has over a guidebook is its ability to use your location. You don't even have to know where you are to ask for "restaurants near me" or "nearest metro stop". And the information is most likely more current than anything in print.
5. A Low Price Point
Travel apps usually cost between $.99 and 2.99. Most free apps won't be enough, but there's no need to spring for the ones that cost as much as a guidebook. For a couple of dollars you really can have a lot of useful information in the palm of your hand.