The latest iOS device retains the same form factor as the predecessor but now includes several upgrades such as the A5 dual-core chip processor, iOS 5, and an better camera (8 megapixels). It also supports a full 1080p HD resolution video recording; and there's a new feature called Siri, an intelligent assistant that helps you get things done just by asking. One of Apple's founders, Steve Jobs passed away on the 5th of October, the next day after iPhone 4S official launch. Many Apple fans believe that the smartphone was called iPhone 4S meaning "for Steve". Jobs's death has a huge impact on the awareness of the iPhone 4S worldwide.
Apple iPhone 4S is a world phone, so both CDMA and GSM customers can now roam internationally on GSM networks. From October 14th, 2011, the iPhone 4S is available in the United States via AT&T and Verizon. In addition, the smartphone is also offered by Sprint, a new carrier for Apple. In addition to regular SMS, messaging on the iPhone 4S is supported by iMessage, its own messenger app and service that allows unlimited texting to other Apple iOS 5 devices. The phone also supports for downloading at maximum rate of 14.4 Mbps on a HSPA+ network.
For more specific info about Apple iPhone 4S, there is a table of specification with more detailed information on the Apple iPhone 4S Specs.