Steve Jobs, the visionary "geek" who changed the way the world looked at technology, has died.

US president Barack Obama led the chorus of praise for the Apple co-founder as even humble consumers flocked to the company's stores around the world to pay tribute.

The pioneering businessman, who was the mind behind the revolutionary iPhone and iPad devices, had been fighting pancreatic cancer and underwent a liver transplant in 2009.

He stepped down from his post as Apple's chief executive in August saying he could no longer handle the job due to his illness. He died in California on Wednesday surrounded by his family. .

Apple's board said in a statement: "Steve's brilliance, passion and energy were the source of countless innovations that enrich and improve all of our lives. The world is immeasurably better because of Steve."

The father of four started Apple Computer with high school friend Steve Wozniak in his garage in 1976 but was forced out a decade later. He returned in the mid-1990s and transformed Apple into one of the world's most powerful companies.

Despite resigning as chief executive due to his health, Mr Jobs said he would continue to play a leadership role. He was replaced by Apple's chief operating officer, Tim Cook, and took the role of chairman of the company's board.

"Those of us who have been fortunate enough to know and work with Steve have lost a dear friend and an inspiring mentor," Mr Cook wrote in an email to Apple's employees. "Steve leaves behind a company that only he could have built and his spirit will forever be the foundation of Apple."

The news Apple fans and shareholders had been dreading came the day after Apple unveiled its latest iPhone, a device that got a lukewarm reception. Perhaps, there would have been more excitement had Mr Jobs been well enough to show it off with his trademark theatrics.

A statement released by Mr Jobs' family said: "In his public life, Steve was known as a visionary; in his private life, he cherished his family. We are thankful to the many people who have shared their wishes and prayers during the last year of Steve's illness."