After the earlier news of a September 7th release it now turns out Europeans will be able to get their hands on the game a tad earlier. As editor Gil pointed out on the forums, a Polish Spore movie puts the release at September 5th. The Dutch EA site puts the release even earlier:

Electronic Arts Inc. en Maxis kondigen aan dat Spore™, de langverwachte game van de makers van De Sims in de winkels zal liggen vanaf 4 september (wereldwijd vanaf het weekend van 7 september) (Translation: Electronic Arts Inc. and Maxis announce that Spore™, the highly anticipated game from the makers of The Sims will be in stores September 4th (world wide from the weekend of September 7th)

So if you live in the US and want the game badly, book a trip over to Europe. Beware of the USD to EURO ratio though!

UPDATE: Germany goes along with Poland on September 5th, France September 4th

UPDATE 2: We put a thread on the forums to keep track of local release dates