They haven't released any actual release information yet. Probably won't see Collector's Edition information until January. The scheduled "leaked" earlier this year has been fairly in the ballpark and it had Q2 2012 for the target release.
I think MoP is going to be awesome. I would say that this expansion, in my opinion anyways, has had the least amount of hype behind it, heading into its release, and I think that works to its advantage. Everything I've seen so far has peaked my interest in the game, it looks beautiful, and I'm excited.
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There are answers you seek, and one of them - I am very sure - is the secret to becoming the most feared level 90 player in your server.
Well, I have a surprise for you because on this very page, you're about to learn the single most effective way to prepare for Mists of Pandaria and you won't need to mortgage two months of your life to do it...
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I've been asked by friends and guildies how this works, and I'll get to that in a second...