Download and app called “Spell Number” from the apps store, you need this app before you can carry on. Don’t worry it’s free but you need the current version which is 1.03

Launch Spell Number, and enter secret digit  91929394.59

Quit Spell Number by pressing the home button and return to home screen. Now open “Settings”
Go to General->Keyboard->International Keyboards->Japanese, and now you will find a new switch called “Emoji”, check it if you want to enable Emoji keyboard. You can also uncheck it to disable Emoji keyboard later.

If you cannot find the emoji option, please reboot your iPhone/iPod Touch.

You should able to see the emoji option after reboot.

Now the Emoji keyboard is enabled, go to any program (I use Notes for example), click any field to popup the keyboard, click the “Earth” icon until Emoji popup

You can also delete Spell Number if you don’t want it, the setting will still be here.