Apple‘s ailing chief executive Steve Jobs made a surprise appearance at a company event here on Wednesday to unveil a new version of the iPad that is thinner, lighter and features video cameras.

“We’ve been working on this product quite awhile and I just didn’t want to miss a great day,” said Jobs, who appeared gaunt but energetic.

The new iPad 2 features front- and rear-facing video cameras to enable video chat and is thinner than the previous version.

It weighs 1.3 pounds, down from 1.5 pounds, and will come in black and white models.

“2010 turned out to be the year of the iPad,” said Jobs, who was dressed in his trademark black turtleneck and blue jeans.

“We sold almost 15 million iPads in 2010 from April to December,” Jobs said. “It generated a little shy of 10 billion dollars in revenue for Apple.

“We’ve never had a product that got off to that fast a start,” he said. “We have 90 percent of the market.

“Our competitors were just flummoxed,” he continued. “They went back to their drawing boards, tore up their designs.”

Jobs, 56, went on indefinite medical leave on January 17, turning over day-to-day operations at Apple to chief operating officer Tim Cook.

Jobs underwent an operation for pancreatic cancer in 2004 and received a liver transplant in early 2009.

Jobs also announced that major publisher Random House would be making electronic books available for Apple’s iBook store.