In case you want to find out complete details of flags of countries all over the world then you can download an app called 'Earth Flags HD' to your iPad. Apart from respective flags of the countries you can also find more information on capital cities, extension areas, calling codes, currencies and internet TLDS of the countries.
You can see maps of many places as well. The newer version has a renovated interface with additional maps such as satellite, hybrid and standard maps.
You can listen to anthems of all the countries covered by the app. New features are added to the app every once in a while. There is a version for iPhone and iPod as well.