The good news: iPAD updated to iOS 4.2, you can install Emoji keyboard by “Emoji for iOS4” ! ! !
How to open the emoji keyboard:
iOS4 – Go to Settings > General > Keyboard > International Keyboard > Add New Keyboard > Emoji.
iOS3 – Go to “Settings >General> Keyboard > International Keyboards > Japanese” and turn ON “Emoji”.
2.Restart your iPhone/iPod Touch (turn it off and on) for the Emoji icons to take place.
3.To use the emoji keyboard in SMS, Mail, Notes,etc. Tap on the globe key several times until the keyboard Emoji up.
If you still can not install emoji keyboard.
First of all, please visit the video, I wish you success.