The World of Warcraft Forums describe the upcoming "before the storm" update for Blizzard's MMORPG (thanks Ant and WoWBreak.com) that will implement the new PvP honor system:

The next World of Warcraft content update, “Before the Storm,” will include the new PvP Honor System, as well as other new features that will prepare us for The Burning Crusade expansion. We are currently planning to release this content update next Tuesday, December 5. Please note that the patch date is still subject to change, and we will keep you informed of any changes to the plan as they happen.

If the patch goes live as planned, this will be the last week that new PvP ranks under the old Honor System can be earned, as the patch will immediately introduce the new Honor System. We will run one final honor calculation on December 5 and update everyone’s ranking accordingly on that date so that players who achieve a new rank for that week have the opportunity to display that title on their character. Please note, however, that no new PvP rewards will be unlocked for purchase with this final “old Honor System” calculation, regardless of any increase in rank.

For those who have been seeking high-rank PvP armor and weapons, note that the new Honor System will still include these item rewards, and it will actually be easier to earn these items under the new Honor System than under the old Honor System. Those who wish to see how their PvP abilities measure up against other players will still be able to do so under the new Arena System.