This past Friday, October 7, 2011, Apple began allowing customers to place pre-orders for the iPhone 4S, the company's next-generation iPhone model that features an improved camera, the A5 processor chip already found in the iPad, and Siri, a personal assistant built into iOS. 

According to Apple's U.S. online store, any pre-orders made for the iPhone 4S from this point on will be shipping in 1-2 weeks, meaning that the company has sold out of units. In addition, that means customers who will be placing pre-orders now should not expect to see their iPhone 4S until after Friday, October 14, 2011, the initial shipping date of the device.

Following this news, according to CNET, AT&T is currently reporting that it saw 200,000 pre-orders of the iPhone 4S alone (the device is also available on Sprint and Verizon Wireless). This number reflects sales placed in the first 12 hours of availability - we're now reaching 48 hours of availability, so the number is likely higher now. 

Finally, Sprint is listing on its website that the iPhone 4S in the 16 GB capacity is sold out. The 32 GB and 64 GB model are still available, however. 

For comparison, Apple announced last year that it saw 600,000 pre-orders for the iPhone 4 in one day.