Jumped on the PTR today and here is some images of the conversation Thrall has with Garrosh and the other high-ranking members of the Horde, ehh Eitrigg....
No voice acting, I wouldn't expect any for an event that will only be on live servers for a month maybe. This is during the Pre Cataclysm events being tested atm on the PTR.
-Jhamantheshaman
castaclysm.com