Blizzard has loosely dated expansion World of Warcraft: Wrath of the Lich King for sometime between October and December this year. According to Blizzard CEO Mike Morhaime:
We have said that it will be coming out this year. I can tell you it's not coming in the July to September quarter.
Awfully kind of him to narrow it down like that. Mike's nice like that, you know. WoW: Wrath of the Lich King Releasing Between October and December [Shacknews]