Bring the Tablet of Jin'yael to Jes'rimon in Orgrimmar.
I have a fence in Orgrimmar. He resides in The Drag. He's difficult to nail down if you don't know where to look, but if you go looking in one of the highest buildings there you should have no problem finding him.
Do me a favor though, don't go shouting to all of Kalimdor that he's there and what his business is--it'd be bad for both of us.
He'll give us more than a fair price for the Tablet of Jin'yael. I'm not sure why, but you should have seen how excited he was to hear about its whereabouts.