Sounds like they have had some issues with their mail servers or some flags in some databases, or both. If they restore some mail-tracking database and lose a sent-flag then it makes sense they'll send it again... and again... until the thing stays up long enough to send the mail AND set the flag. Hopefully they're not hooking anything else up to that flag. Like a counter of phones to set aside from the pre-order stock...
I feel fortunate just to have received one each of the two expected emails, the second of which assigned a shipping order number and says a third email will fly when the thing ships.
Still cannot see my order data in my account overview, though. Sigh. At one point I was really excited when I saw the expected array of data pop up, then I realized their system had worked really hard and managed to fish out my prior upgrade order info from back in 2009. Geez! Well eventually I'll get a 4S. Their rep says the status is fine even though my order confirm hasn't hit the accounts database yet.
I hope they make a ton of money selling 4S, they are going to need it to pay their reps not to quit before launch day!