If you've got bugs in your products you'd assume the company who made them is going to fix them, but it's reassuring that Apple's come out and said it specifically. Apparently Cupertino's identified the bug that's killing iOS 6.1 iPhone batteries, and is in the process of crushing the life out of it. Meanwhile, here's what you have to do to stop it for now.
Apple's support note basically describes the same steps as Microsoft did, trying to help out its Exchange server users. The bug is caused when "you respond to an exception to a recurring calendar event with a Microsoft Exchange account on a device running iOS 6.1." It causes the device to "generate excessive communication with Microsoft Exchange Server" draining your battery and causing issues for the server while it's at it.
Apple suggests the following until it manages to push out an update:
1. Go to Settings > Mail, Contacts, Calendars
2. Select the Exchange account from your Accounts list.
3. Turn the switch for Calendars to OFF.
4. Wait ten seconds.
5. Turn the switch for Calendars back to ON.
Let's hope Apple gets things fixed up and pushes out an update for the insane battery drain sooner rather than later. Oh, and it better not patch up the Evasi0n jailbreak hole while it's at it. Then I really would be pissed. [Apple]