Although Apple had announced that their newest iPhone smart phone (the iPhone 4s) will only be available starting November this year, you can already get buy an iPhone 4s (and get it) right now.
Reports say that Apple had already allows you to buy iPhone 4s phones in their USA retail shops. These iPhones come without a contract and are therefore sim-free cell phones.
Prices had been reported to be starting at 649$ for the 16GB model, 749$ for the 32GB model and up to 849$ for the 64GB model.
People who bought the new iPhone 4s in the Apple store reported that once you plug them in and start your iTunes, the device gets unlocked, allowing you to use any sim card you want (as long as it is a GSM card).