If you were planning to preorder an unlocked iPhone 4S today, you're going to have to wait a little while. The unlocked and contract-free version is available starting in November, with no specific date listed on the Apple website.
There's another bit of a surprise, although it makes sense: the unlocked iPhone 4S won't work on CDMA carriers like Verizon Wireless and Sprint. Why does this make sense? Most of the world currently runs on GSM networks. Even though the iPhone 4S is touted as a "world phone" that can run on both GSM and CDMA networks, most of the people who will use an unlocked, contract-free phone are like world travelers who need the ability to swap a micro-SIM card to get on a new local GSM carrier.
For some reason, Apple is also warning that potential buyers of the unlocked GSM iPhone 4S may require a credit check, and that they must be at least 18 years of age to make their purchase.
The pricing on the contract-free iPhone 4S is fairly steep as well. The 16 GB version starts at US$649, the 32 GB model is $749, and the 64 GB model will retail for $849. The contract-free GSM iPhone 4, which Apple started selling in June of 2011, also sold at similar prices.