Apple today announced it has sold over four million of its new iPhone 4S, just three days after its launch on October 14. In addition, more than 25 million customers are already using iOS 5, the world’s most advanced mobile operating system, in the first five days of its release, and more than 20 million customers have signed up for iCloud, a breakthrough set of free cloud services that automatically and wirelessly store your content in iCloud and push it to all your devices. iPhone 4S is available today in the US, Australia, Canada, France, Germany, Japan and the UK, and will be available in 22 more countries on October 28 and more than 70 countries by the end of the year.

“iPhone 4S is off to a great start with more than four million sold in its first weekend—the most ever for a phone and more than double the iPhone 4 launch during its first three days,” said Philip Schiller, Apple’s senior vice president of Worldwide Product Marketing. “iPhone 4S is a hit with customers around the world, and together with iOS 5 and iCloud, is the best iPhone ever.”

Apple will launch iPhone 4S in 22 more countries including Austria, Belgium, Czech Republic, Denmark, Estonia, Finland, Hungary, Ireland, Italy, Latvia, Liechtenstein, Lithuania, Luxembourg, Mexico, Netherlands, Norway, Singapore, Slovakia, Slovenia, Spain, Sweden and Switzerland on October 28. That should further increase iPhone 4S sales.