Apple, as part of their Apple iPhone OS 2.2 update, enabled Emoji icons for the Apple iPhone users in Japan that are running of the Softbank network and include 461 Emoji characters.
Steven Troughton-Simth, a 19 year old software developer walks us through just how to enable Emoji icons system wide, although if you are not familiar with editing code it is not recommended you try this.
According to Smith… “You need to edit the file /User/Library/Preferences/com.apple.Preferences.plist on the device -> whether you use a jailbreak to achieve this or merely some iTunes backup editor is up to you.
Add the following boolean key as ‘true’: KeyboardEmojiEverywhere
Then merely go to the Keyboards section of the Settings app, hit Japanese, and turn on Emoji. Will work for any text field/view in the OS, including on websites, AND including the titles of items on SpringBoard (e.g. if you save a bookmark to the home screen).”
Source — macblogz