Although they haven't released specific numbers, Sprint reported record sales less than half way through the day the new iPhone went on sale.
Verizon also hasn't released sales figures, but we should know more after their earnings call which is scheduled for today. Don't be surprised if those numbers are less impressive.
Unlike AT&T, who was the exclusive US iPhone carrier until last February, Verizon sold their first iPhones earlier this year. That should translate into fewer immediate upgrades from the iPhone 4, and obviously none from earlier iPhones.
That may, however, be a good thing for Apple. It could mean steadier US iPhone sales through next year, with Verizon customers upgrading later.
Since the iPhone 4S lacks LTE capability, which means it won't be able to take full advantage of Verizon's 4G data network, some Verizon customers may even wait for the next iPhone upgrade in the hopes LTE support will be added.
But if previous iPhone launches are any indication, those people will likely be in the minority.