UPDATE: Blizzard have now confirmed the release date.
Over at TeamLiquid, poster Waxangel put up this screenshot from Blizzard’s online store, adding that the Korean pre-order price looks to be about 36,000 won, equivalent to $33. However, I can’t find Heart of the Swarm in Blizzard’s European store. Amazon.com also have the game listed for a March 12th release date while, again, Amazon.co.uk have nothing for us, yet.
The Blizzard store is currently down for maintenance, but once it’s back up you should be able to reserve your copy now, should you wish.