If you just can't wait to read the Wotlk Manual, Maeglin of Khadgar made an interesting discovery -- it's already on your computer. Inside your WOW folder, if you go to the WOW Data folder, and then "enUS" and Documentation, you'll see a PDF file called Manual_WLK(It’s Wotlk Manual). It's the Wrath Manual in black and white -- there are good writeups in there (spoiler-free, as far as I could tell) on the story so far and Northrend, and some cool concept art for weapons and other sights of the next expansion. The credits are in there, too, and make sure to go to the very end to read all the thanks from Blizzard -- some of them are pretty funny.
This likely isn't the final Lich King Manual -- there's something in the Death Knight description that still says runes can be customized, and while we heard that earlier in development, it's since been removed from the class. And it's in black and white, while we'd expect the full Wrath Manual to have color when it's finally printed. But it's a cool find, and something to tide you over until you can get the real thing on Wotlk Release day (which, as you can see from our countdown, is growing ever closer).
WOTLK Secret:Wotlk Manual