It was announced on the Blizz WoW twitter feed last night that Cataclysm is going to be available on December 7th 2010. This fits with MMO-Champion's datamining finding that Season 9 will be starting on December 14th.
Well, I know what I am buying myself for my birthday!
What surprises me is that no one seemed to have noticed that little announcement on twitter. I was surprised that it slipped by the people I follow.
Anyway, Happy Cata!
ETA: I originally predicted June as a release date for Cata. When it became clear that was not on the cards, I revised my date to late November/early December. However, 7 December makes me happy, because I will be back from sydney in time to enjoy Cata!! The next question - do I try to get a collectors edition?