Apple chief executive Steve Jobs, who spent months on medical leave, will open an annual developers' conference next week showcasing the company's latest software and a new cloud computing service.

The company said it will unveil a new cloud-based service called iCloud, which will offer remote computing power and data over the Internet.   

It also plans to unveil software upgrades at the conference including Lion, the eighth major release of its Mac OS X computer operating system, and iOS 5, the next version of its mobile operating system used in products including iPhone and the iPad.

Apple typically unveils a new iPhone this time of year but some sources had told Reuters they did not expect the new model to appear until September.   

Wall Street speculation has centered in recent months on the launch of a cloud-based multimedia service that will let consumers store and stream music. Apple has struck deals with three of the four major record labels, sources have said.   

Apple's shares rose almost 2 percent after it said on Tuesday that Jobs and a team of executives will kick off the June 6 conference with a keynote speech, without making clear exactly what role Jobs would play or if he is returning from medical leave. 

An appearance by Jobs, a survivor of a rare form of pancreatic cancer, would mark one of the few occasions he has appeared in public on the company's behalf since he went on his third medical leave -- for an undisclosed condition -- in January.

In March, a thin but energetic Jobs took to his now-familiar platform at San Francisco's Yerba Buena Center to unveil the iPad 2, drawing a standing ovation after months of frenetic media and investor speculation about his health.

"It's a good sign he's healthy enough to be there and participate," Pacific Crest Securities analyst Andy Hargreaves said, but he added that "it's not a huge surprise" because of the executive's appearances at other events.

Jobs, 55, a high-tech visionary who has come to embody Apple's turbulent history and some of the industry's most cutting-edge products, is credited with rescuing Apple from near death in 1996 after a 12-year absence from the company he co-founded.  

Under his leadership, the launch of the iPhone, a smartphone with a touchscreen in 2007, and the iPad, a tablet computer in 2010, forged new business lines for the company that created the personal computing category.

In January, he took his third medical leave in seven years, but executives say he has remained involved in strategic decision-making. -Reuters