The pre-order page for player accounts now includes a link to download and install the client, assuming that you've entered the code you received when you ordered. Curiously, this latest announcement says that players can receive up to seven days of early access, although that may well be a typo. If you'd missed previous announcements, players who took part in a beta weekend prior to November 24th will need to reinstall the game, so go ahead and download the updated client and get ready for the early launch in a few days.
[Update: Darth Hater has collected several forum and Twitter posts that confirm the December 13th date is not a typo and is "different from previously advertised." Early-early-access, here we come!]