The announcement was made at Apple's headquarters in California. Apple has unveiled the latest iteration in its iPhone range, but there was no sign of the widely rumoured iPhone 5. The iPhone 4S, as the new model will be known, boasts an improved camera and significantly extended battery life.
It will run on the latest iOS5 operating system, which is set for release on 12 October.
The event was the first major announcement for new CEO Tim Cook who took over from Steve Jobs in August.
The iPhone 4S, to be released on 14 October, will be available in 16GB, 32GB and 64GB models - in both black and white.