Civilization Network, the Facebook incarnation of the legendary franchise, will be launching in 2011, according to statements made by Take-Two's Strauss Zelnick (via Joystiq).
The game's Facebook page, however, has not been updated in quite some time. The title has been in beta-testing since June of this year. The game was originally announced in October 2009.
It remains to be seen how this title will differ from the classic Civilization gameplay we all know and love. I'm guessing it will be closer to FarmVille or other "management" style games than a true Civ, but that's fine for the Facebook audience. Also, it will probably have micro-transactions. Sad face.