I think they said something about a FREE Open Beta Test in USA/Austrailia/New Zealand starting some time soon. There is also supposed to be an Open Beta Test in Europe at a later date.
Metabee, You can only sign up for the Stress Beta if you got the European Beta, and you are way to late. The Sign-ups was in the summer (½ year ago). So its kinda impossiple for you to register...
*Note* Blizzard has made this as the last Stress Beta Test, after that they have replied in the WoW Forums that the Open beta would come right after the Stress Beta, and you also need an European Beta E-mail for registering.