NYTimes: "What can you tell me about Naxxramas?"
Tigole: "Naxxramas is going to be the most difficult thing in the game until the expansion pack comes out. It will be the pinnacle, and it's absolutely massive. You'll see this big necropolis floating above Eastern Plaguelands. It's a 40-man raid zone, and it's bigger than the Undercity [one of the main cities in the game]. Things could change, but we're up to something like 18 bosses in there, and they are really cool, too. But it's going to be hard. Really hard. We're hoping to release it in the spring."
Links
NYTimes.com - Interview