Ensidia

Amazon has put up their pre-order pages for World of Warcraft: Cataclysm, priced $39.99.

If it follows TBC and WotLK trends this would mean that the expansion is coming out in 3-4 months, but this is probably more of a sales approach by Amazon. On the other hand, perhaps Blizzard have realised that 6-8 months of farming the last instance before a new expansion for basically no reason whatsoever (since most of the gear will be outdated by the time you ding 70,80 or 85) isn't such a good idea.

In any case it's always good to have a pre-order locked up, just in case.

Europe/UK pre-orders here, US/Canada pre-orders here.