As reported on his tumblr blog, Notch will officially be stepping down as lead developer of Minecraft. His awesome partner in crime, Jens Bergensten, will be taking his place:
We’ve been working together on Minecraft for a year now, and I’m amazed at how much in synch we two are when it comes to how to design the game. And when we don’t agree, we discuss it and something much better comes out at a result. He’s truly a great person to work with, and I feel very confident handing over the leadership of Minecraft to him.
...Personally, I will now rest for a while, then get back to work refreshed and eager. I’ll be helping out with Minecraft, of course, but also starting work on some new project.
This isn't particularly surprising. Jens, otherwise known "Jeb", has been in charge of the game for a while now, some say a few months and others say a year. I think Notch deserves a rest anyway, what with the ridiculous lawsuit between Bethesda and Mojang over the world "Scrolls" and, well, his work on Scrolls itself.