Daniel Kaplan (@Kappische on Twitter) Is the lead iOS Developer for Mojang, the company that make Minecraft. He has uploaded a few teaser pictures of Minecraft for iOS on his Twitter account.
The game looks basically like a port of Minecraft Pocket Edition for Android on iOS. He released a picture on Imgur, it is at the top of the post. He also released a picture today:
The picture was from “Photos on iOS” so he was testing it and it works on iOS 5.
Stay tuned for more info!