Has anyone else noticed that Apple has charged your credit card for Snow Leopard? I checked my credit card today, and there was a temporary authorization for $10.24 from the online Apple Store (the cost of the upgrade DVD--I purchased a new Mac in June). To me this seems like a really good sign that it will ship soon. They usually don't charge credit cards until it ships. My guess is that we hear an announcement from Apple tomorrow!
That was a pre-authorization not the sale transaction. When you use a credit card for an authorization the retailer must request funds/see if the funds are available. They basically ask if the money is in the account and request a hold on the funds. Those funds are not immediately transferred. Some retailers, like a gas station, may request an authorization of a set dollar amount, say $75. So even if you do not want to purchase $75 worth of gas they put a hold on that amount. If you do not have $75 in the account you get declined before pumping the gas. If it clears, that $75 is put on hold. It stays in your account but you cannot use your credit card to use it.
After the money is put on hold they need to "close the batch" with your sale included. This tells the intermediary to tell your bank to send that money, or portion thereof, over to the intermediary (the banks do not talk to each other and this is a greatly simplified description of what really goes on). The intermediary then sends the money, minus service fees, to the retailer. The important thing to know is that the retailer can only do this when the product is shipped. They can put a hold on the funds but cannot request the funds be transferred (and this is a often used technique by people who lift credit cards or credit card numbers — test to see if there is money available and then withdraw the funds or use it at a site that might not have the most up-to-date security measures in place)until after they ship the purchased products. Anyway, you generally do not see the final transaction until a day or two after the submittal. Oh, and yes, there are more efficient and less expensive ways of doing all of this.
More to the point: Apple has to use that money or your bank will let it go after a certain amount of time. You may see another authorization at 30, 45, or 60 day internals. Still, this is not the final sale. The bottom line is that the pre-authorization is not iron clad proof that SL is shipping now or next week. Late September, October is as good a guess as any.