If you're wondering how long the WoW Beta test will last, here is news for you. Katricia gives us a first guess on Beta duration:
Historically, beta tests last approximately 2-3 months. Due to the depth and magnitude of the World of Warcraft beta, we expect the beta test to last at least this long. We will notify participants when the beta test is nearing completion.
But there are other factors to be accounted for if you think about the total duration of the Beta and, in particular, the final game release:
sometime in the future, the Beta a) may include more players of "Beta countries" and b) will expand to other countries, including Europe; this may add up to the Beta duration
"When it's done": Blizzard's mantra will play an important role in Beta duration; they will only end the Beta when they're really satisfied with what they see
there will be a shorter or longer period after the Beta to finalize WoW and prepare it for going Gold (i.e., the creation of master CDs for mass CD production)
Blizzard announced a parallel world-wide release of the game, so if they stick to their promise, it will take some time until all resellers have received their copies of WoW