Apparently there is a new Indie game on the xbox live marketplace called "FortressCraft". It is the EXACT same thing as minecraft, except for improved graphics.
I think November 11th, Minecraft is becoming a real game and leaving BETA and then they are going to work on the xbox version, which they say it's coming "Later this year" so who knows when.
This has been know for quite some time, I used to play the FortessCraft XNA builds (In April/May), IMO this game is nothing compared to the PC version, it disappointed me,