WHAT IS Emoji?
emoji originating from Japan is a special set of images and emoticons to be use in messages, emails, etc. Start from iOS 5, Apple built-in emoji keyboard.
To enable:
1. Settings > General > Keyboard.
2. International Keyboards
3. Add New Keyboard...
4. Scroll down and choose Emoji
To access:
1. Tap the globe icon next to Space bar
2. Tap the icons at bottom of the keyboard to switch themes
3. Tap the clock icon next to the globe icon to access recently use Emoji.
URL: http://howto.cnet.com/8301-11310_39-57341289-285/how-to-enable-ios-5s-native-emoji-keyboard/