Blizzard has thrown together a FAQ to cover all major questions with the upcoming expansion’s release. Here are some of the major ones:

When is the official launch time for the Burning Crusade?
The official launch time is 12:00 AM (midnight) EST on January 16th.

Where do I need to enter my key when upgrading? Is it through the client or on the website in Account Management?
You will need to enter your key at the Account Management page to upgrade your account to access The Burning Crusade. We will have a link on the main site for players to access it.

Will there be Tuesday Maintenance, or will I be able to play without planned downtime?
There will be no scheduled maintenance for release day, though should it be deemed necessary, we may have rolling restarts.

Will everyone receive a free respec upon release of the expansion?
No. There will be no free respecs with the release of the expansion.

Full FAQ here.

Posted by: Draiken