Do you want to be able to send emoticons to your iPhone buddies? Here's how:
1) Go to the App Store and look for the free app called: Spell Number.
2) Start Spell Number and type the number blow, the hit return a few times. You can then close the application.
3) Go to Settings->General->Keyboard, scroll down to Japanese, and enable Emoji.
4) Now, go ahead and start typing. You can switch back and forth between your keyboards by pressing the internationalization button (Globe).
If you have a Jailbroken iPhone, you may encounter some missing buttons like below. The left one is for switching, the right is the backspace key. They do work, but, no button is shown.