According to CVG Blizzard will be selling a Wow Authenticator at Paris to secure your World of Warcraft account:
For six Euros, you can buy a WoW Authenticator in Paris this weekend that will make it almost impossible for someone to use your Warcraft account unknowingly. They will also be available through the Blizzard website sometime after.
Designed to attach to a keychain, the device generates a six digit number at the touch of a button. In order to access your WoW account, you have to type in that random number every time you wish to log in.