There is no built in emotion icons in the iPhone FW but there are 3rd party apps that can be used for emotions.
Does it work- 5.0
The iPhone's emoji icon app uses the global keyboards, in settings. This application was very well designs and you never need to launch the app itself. When you first purchase and download this app you first need to go to settings then general and keyboards, next you need to scroll and find Japaneses and turn on Emoji. The only problem with this app. is that it does not work with other cell phones only iPhones, and it does not show up on any computers. Overall, this app is worth the dollar, to get tons of emotions on your iPhone.