The iPhone (2.2 +) comes pre-loaded with Emoji icons but the menus to turn them on aren't enabled. If you aren't familiar with Emoji icons they are popular pictures/emotions used in Japanese wireless messages. The iPhone comes pre-loaded with these little icons but the menus are disabled.
Aside from the Cydia download to enable them there are many applications on the AppStore like Typing Genius ($0.99) and Spell Number (free) that enable these Emoji icons. Apple doesn't seem to like developers on the AppStore enabling this Easter egg on its devices. Apple removed the application