Many customers have been queuing overnight to get their hands on the iPhone 4S, which was officially announced at an Apple press conference last week.
At Apple's Fifth Avenue store in New York City, at least two people have been camping out in front of the store waiting for the device since September 26.
> Apple's iPhone 4S launches across the world - pictures
CNN has even reported that Steve Wozniak, the Apple co-founder, is currently at the front of the queue in his hometown of Los Gatos in California waiting to get the iPhone 4S. Apparently he's sat in a Pico armchair "sipping Diet Dr Pepper and scanning e-mails from his white iPad".
Powered by the dual-core A5 chip and Apple's latest iOS 5 operating system, the iPhone 4S features an eight megapixel camera, full HD video and voice control system Siri.
The iPhone 4S is available in either black or white. The 16GB handset costs $199 and 32GB $299. It is also the first iPhone to feature a 64GB model, priced at $399.
The same story is true in the UK, Australia and four other countries where the iPhone 4S will today become available.
Many people have opted to avoid the queues by pre-ordering the handset online from Apple, or via the various contract offers from one of the major mobile carriers.
The launch of the iPhone 4S comes as Apple struggled to keep up with demand for its new iOS 5 operating system, which went live on Wednesday with users reporting various issues and problems trying to download it.
Apple iPhone 4S press conference round-up:
> New Apple iPhone 4S - in pictures
> New iPhone 4S: Was it worth the wait? - poll
> iOS 5 to launch on October 12, says Apple
> Apple product launches down the years - Pictures