Apple Computer co-founder and CEO Steve Jobs has announced his resignation, according to a statement issued by the company.

In the statement, Apple announced that Jobs, who co-founded Apple with Steve Wozniak in 1976, stepped down August 24 and will be replaced at Jobs's suggestion by chief operating officer Tim Cook.

"Steve's extraordinary vision and leadership saved Apple and guided it to its position as the world's most innovative and valuable technology company," Art Levinson of Apple's board of directors said in the statement. Jobs now assumes the position of chairman of the board.

"I have always said if there ever came a day when I could no longer meet my duties and expectations as Apple's CEO, I would be the first to let you know," Jobs wrote in an open letter to the board of directors posted on the Apple Web site. "Unfortunately, that day has come."

Although no reason for his resignation has been given, Job's health issues in recent years, including a liver transplant and a battle with pancreatic cancer, have led to much speculation about his future with Apple. Cook is an unsurprising choice for his successor, having led the company on an interim basis when Jobs took medical leave in 2004, 2009 and again earlier this year, according to Mac World.