What models of iPhone 4S are for sale in the US
All models come in white or black at the same price, so we'll list them by capacity and locking status by increasing price.



Unlocked GSM Phones

All these ship without a micro SIM (Coming in November)


16 GB - $649 - GSM unlocked - no contract or subsidy 
32 GB - $749 - GSM unlocked - no contract or subsidy
64 GB - $849 - GSM unlocked - no contract or subsidy




AT&amp;T

AT&amp;T iPhone 4S will be configured to use GSM domestically and GSM roaming. 

Comes with AT&amp;T micro SIM (all ship 1-2 weeks currently)


16 GB - $199 - GSM locked - with 24 month contract &amp; subsidy
32 GB - $299 - GSM locked - with 24 month contract &amp; subsidy
64 GB - $399 - GSM locked - with 24 month contract &amp; subsidy




Sprint

Sprint iPhone 4S will be configured to use CDMA domestically and GSM roaming. 

Sprint iPhones may or may not be unlocked internationally out of the box Even in this article, there is currently some confusion and flip/flopping on this point.


16 GB Sprint CDMA - $199 - GSM locked - with 24 month contract &amp; subsidy
32 GB Sprint CDMA - $299 - GSM locked - with 24 month contract &amp; subsidy
64 GB Sprint CDMA - $399 - GSM locked - with 24 month contract &amp; subsidy




Verizon

Verizon Wireless iPhone 4S will be configured to use CDMA domestically and GSM roaming.

After 60 days in good standing, Verizon will unlock the SIM for international use upon customer request, but it remains locked within the US.


16 GB VZ CDMA - $199 - GSM locked - with 24 month contract &amp; subsidy
32 GB VZ CDMA - $299 - GSM locked - with 24 month contract &amp; subsidy
64 GB VZ CDMA - $399 - GSM locked - with 24 month contract &amp; subsidy




This answer is community wiki - please improve it in any way you please