When is the expansion coming out? is the #1 thread on the official forums next to why Leeroy Jenkins and Chuck Norris would make a great standup comedy team.

The release of World of Warcraft: Wrath of the Lich King is highly anticipated by the entire playerbase. Guilds are slowing down their progress, gold farming is taking priority over gear, and everyone is waiting with baited breath on the latest news of the release. David "Xerin" Piner takes up the magic 8-ball and tries to divine the release date based on Blizzard's past history and current evidence laying about the Internet. So be sure to check it out to get an idea of when the expansion may launch.

The first thing to realize is that any date before BlizzCON 2008 is a wash. There is no way they’d release the game before the convention. As a matter of a fact the launch date will probably be told at BlizzCON. So let’s go ahead and say that a month after BlizzCON would be the most logical conclusion on a release date. So let’s say November is the earliest (which is probably the same conclusion the Gamestop Warlocks came up with).

WoW: Wrath of the Lich King's Launch Date Editorial - Just when will it come out? is a good start in trying to divine the launch date for the expansion!