Just this weekend a colleague was telling me about his intention to make his shaman from Draenei to Dwarf. I have bad news my friend ardon… you won't be able until Cataclysm arrives!
Although the new Race / Class combinations will be available with Patch 4.0.3a, we will not be able to change until December 7th.
Swapping out the new race / class combos will also be available once Cataclysm arrives on December 7th. There will be a period of time between the Devastation and the launch of Cataclysm in which new combos can be created but we cannot switch to them. Like everything, this could change.
So while you will be able to create a Shaman Dwarf or Paladin Tauren right after the Devastation, you will not be able to change an existing character into any of the new race / class combinations using the Race Change service until we launch Cataclysm.
If this changes, we will let you know.
Does this disrupt your plans a lot? Did you plan to change this week?
Edit: It looks like Blizzard will finally allow you to switch races as soon as patch 4.0.3a is live