According to Kotaku, the new Alliance race is none other than the Draenei. Now here is where it gets interesting though. You see this rumor and supposed confirmation of said rumor comes from Parting Visions and their scans of the February issue of Computer Gaming. But hold on, Blizzard comes along now. They will not confirm nor deny this story in fact. The only thing Blizzard has said is that they have not released any information on the new Alliance race to any website, magazine or other media source.
They of course welcome the debate and continued speculation.