In case you were wondering, however, wonder no more. MMO-Champion has all the details (plus screenshots), courtesy of Arthyn from Vanquish (A-Staghelm). In short, you have to kill Fathom-Lord Karathress (a boss in Serpentshrine Cavern) and Al'ar (a boss in the Eye). The detailed version is after the cut, for reasons of length and spoileriness.
Update: apparently, Karathress and Al'ar are just the first parts of the attunement chain. After Al'ar, you have to kill Rage Winterchill, the first Hyjal boss, and even that may not be the end -- we'll just have to see. World of Raids has screenshots of the new quests.
"After killing Karathress, our guild was able to pick up a quest from Seer Olum. He spawned in the spot where Karathress stands. He gives a quest called The Secret Compromised which tells you to go to the Warden's Cage to talk to Akama. After a cutscene with a conversation between Seer Olum and Akama, Akama talks to Illidan. Illidan then tells Akama to kill Al'ar. Akama then gives you the quest Ruse of the Ashtongue which requires you to kill Al'ar wearing the Ashtongue Cowl. The Ashtongue Cowl gives you the appearance of an Ashtongue while in Tempest Keep. Upon using the Ashtongue Cowl in Tempest Keep, a buff called Ashtongue Ruse is applied to you giving you the appearance of an Ashtongue. The buff lasts through death but is removed when zoning. Screenshots of the conversation and what wearing the Ashtongue Cowl looks like [are up at MMO-Champion]"