There was a Cataclysm Q&A recently which revealed some nifty information. Most importantly, the new class/race combos will be available before launch, possibly with the 3.9 patch.
Sauce: http://wow.battlenet.pl/portal/wow/1..._Gamescom.html
It's like a half hour long. There's a nice summary of highlights here: http://www.worldofraids.com/topic/17...ot-interview/?