Apple has begun taking unlocked iPhone 4S pre-orders in the US Online Apple Store. The preorders list a 1 to 2-week ship time and and are available for all three storage capacities in white and black. I just put an order in for my unlocked iPhone 4S and the confirmation email lists a delivery date of between November 28 - December 5. Currently unlocked iPhone 4S pre-orders are for delivery only and cannot be placed online and then picked up in an Apple retail store.
Unlocked iPhone 4S models come in both white and black and cost US$649 for the 16 GB version, $749 for the 32 GB version, and $849 for the 64 GB version. Unlocked iPhones allow a user to simply insert a carrier's micro-SIM card in to use the phone on any GSM network in the world. The unlocked iPhones will not work on CDMA networks, including Sprint and Verizon in the US.