I would like to give you some App recommendations for your trip to Barcelona. Not all directly relate to the city, but still make sense traveling there and making life a little easier. Warning: most of the apps will need a mobile (3G) or WiFi internet connection.
Price: 4,99 € (check actual price in Appstore)
Nicely made Barcelona travel guide for iOS. The app even combines a daily plan depending on length of stay. Also has offline maps. Good idea!
Price: 2,99 € (check actual price in Appstore)
The well-known Lonely Planet Guide for Barcelona in its iOS-Edition – what more to say!
This is the little brother of TMB Maps and made for the iPhone. You will find the next station and schedules with this smart app.
This app is not much more than a virtual photobook. Although it contains very nice and historic photographs of different corners of Barcelona. Nice to see!
Location Scout is a cool idea and of course works out of Barcelona, too. According to your geo position the Internet Movie Database is queried for movie locations nearby. You can then navigate to it. Several movies have been filmed in Barcelona. Sightseeing for cinema enthusiasts.
Quite interesting App: it reads your gps-position and display nearby shops, hospitals and other services by categories.
Price: 0,79 € (check actual price in Appstore)
Whatsapp Messenger is kind of the standard in mobile messaging now. You can send free messages, photos, gps-position and more between iPhones, Blackberries and Android-Phones. Very good to plan meetings and organize yourself with others.