You can preorder from GamersGate from
here; for those who don't know, the Hearts of Iron series are wargames/simulations of the World War II era. Each is incredibly detailed and involved, and this third installment looks to be even another level of complexity greater. Not at all the kind of game for the casual gamer, but great for those who like to explore alternative historical outcomes, and those who love the feel of moving millions of men and machines into combat.
The game engine has been completely revised from previous Paradox games, so it'll be interesting to see how it plays out - the screenshots look much better than previous games, which seemed to be stuck about 5 years behind the times. I expect I'll be retreating like a hermit into the computer room for a few weeks, if not longer, when I get my copy.