Has Notch sold Minecraft/Mojang to Microsoft?

Not yet, but insider reports state that both parties are in discussions for a $2 billion acquisition.

EDIT: What makes you think that Microsoft will ruin the franchise? The developers will be the same, the project gets funding from Microsoft (who have nearly unlimited pockets of cash since they dump at least $50 billion a year into R&D), and Microsoft has already proven to be friendly towards the franchise. Notch makes out like a bandit, Microsoft makes a ton of cash from franchising opportunities, and Mojang gets tons of better resources from Microsoft.