If you've been reluctant to chain yourself to a carrier for two years, then good news: As promised, Apple is now selling an unlocked, contract-free version of the iPhone 4S. Keep in mind, it'll cost you a pretty penny.
When the company introduced the iPhone 4S last month, it said an unlocked option would arrive in November. Besides the lack of a contract, the main benefit of the unlocked iPhone is that if you travel internationally, you can swap in a SIM from a provider in that country and pay domestic rates.
Here in the U.S., however, you'll still be limited to a GSM carrier: AT&T--if you want full 3G service--or T-Mobile. Though the iPhone 4S also supports the CDMA technology used by Verizon and Sprint, you can't use the unlocked iPhones on those carriers' networks.
Of course, as mentioned, you'll have to pay a premium for the unlocked model, since it doesn't benefit from the subsidies provided by the carriers. The 16GB version will run $649, the 32GB goes for $749, and the 64GB model costs $849. Apple quotes 1-2 weeks shipping time for all three capacities, so in addition to paying more, you'll also have to wait a bit. But, depending on your situation, it may be worth it.