Also, here's a forum thread with ton of info.

Here's some of the more relevant things (selected by Gametrailers):

• Releasing in 2013 for PC/Mac.

• ZeniMax Online's 250 Person Team began development on the game in 2007.

• Takes place 1,000 years in the past.

• Fully voice acted & features a third-person perspective.

• The game uses a hotbar to activate skills like other traditional MMOs.

• Crafting, alchemy, and soul gems will be included.

• There will be Daedric Princes like Molag Bal, who acts as the game's primary antagonist.

• There are three player factions:
Ebonheart Pact: The Nords, Dunmer, and Argonians
Aldmeri Dominion: Altmer, Bosmer, and Khajit
Daggerfall Covenant: Bretons, Redguard, and Orcs.

• Hitting the level cap takes roughly 120 hours.

• The game features three-faction PvP, which has players fighting to take over keeps and using siege weapons.

• 100 v 100 battles will be possible.

• The most accomplished PvP player on your faction becomes Emperor upon taking control of Cyrodil's Imperial City.