Updating Northrend?

Q u o t e:
If I'm leveling a character in Cat, during a time after the defeat of the Lich King, how is when I travel to Northrend, the Lich King is still alive and kicking, or will Northrend quests and zones also be updated?

There is going to have to be a certain amount of suspension of disbelief on your part. The Wrath of the Lich King expansion exists on its own as its own timeline and story. While it would be great if we could eventually mesh the storylines all the way up through Burning Crusade and on into Wrath of the Lich King, that is something to be decided upon at a later point in time if we feel it's something we want to delve into more. It would take a phenomenal amount of work, much like what we've already been doing with the old world.