Apple Computer showcased its Leopard operating system, due out next year, to the cheers of software developers gathered for a major conference.

With its trademark theatrical flair, the maker of Macintosh computers and iPod music players demonstrated new Leopard features that included playful "iChat" video-conferencing and a "Time Machine" that resurrects lost data.

"With our entire digital lives on the computer, Time Machine is none too soon," Apple chief executive Steve Jobs said in an opening speech to a packed auditorium. "We think iChat for Leopard is going to be a grand slam."

Apple gave a preview version of Leopard software to developers at the conference so they could begin crafting applications to complement the operating system, Jobs said.

"We are working very hard on this and think we will get it out next spring," Jobs said, disappointing some in the crowd who had hoped for an earlier release date.

More than 4,200 software developers from 48 countries registered for the week-long Apple conference, according to the company.

Rival Microsoft, whose software powers 90 percent of the world's computers, plans to release its own new operating system, Vista, in January.

Apple executives taking part in the demonstration lampooned software colossus Microsoft and the delayed release of Vista.

"Our friends up north spend over five billion dollars on research and development and all they seem to do is copy Google and Apple," Jobs quipped, referring to Microsoft's headquarters in Redmond, Washington.

"I guess money isn't everything."

Jobs told the receptive audience that some Leopard features were going to be kept secret because "we don't want our friends in Redmond to start their copiers any sooner than necessary."

"If you can't innovate, I guess you imitate," Apple vice president of software engineering Bertrand Serlet said as a picture of an obese Elvis Presley impersonator was displayed on a wall screen behind him.

"But it is never quite as good."

Macintosh computers were gaining market share on Microsoft-based PCs, Jobs said, noting that Apple shipped 1.33 million in the last fiscal quarter.

Apple has been leveraging the popularity of its market-dominating iPod MP3 players into converts to its cult following of Macintosh users, according to industry analysts.

Leopard features touted at the Apple Worldwide Developers Conference 2006 were true to the company's hip style and historical focus on making tasks easier for computer users.

"I am very impressed at the rate with which Apple introduces new technology into its operating system," said Mark Taylor, an engineer at Software Imaging Ltd. of Oxford, England.

"They have really been listening to responses from users."

Time Machine was inspired by a survey that indicated only 26 percent of Macintosh users regularly backed up information on their machines to avoid losing it forever in system crashes.

The feature automatically copies music, pictures, applications, files and "absolutely everything" a person puts on their Macintosh, according to Apple vice president of platform experience Scott Forstall.

"If your hard drive dies you can buy a new hard drive, put it in the machine and be right back where you were before," Forstall told the gathering. "It is that easy to go back in time and bring back things you want to restore."

The operating system enabled people to remotely search for files on all computers connected to their network.

Leopard also had simple tools for people to create "widget" applications that stream feeds from websites onto small windows on computer screens.

For example, a Macintosh user could keep a continuously updated best-selling book list or the views from chosen web cameras on a desktop screen, Forstall demonstrated.

Leopard was also designed with better text-reading, Braille support, and closed captioning for people with disabilities, Jobs said.

Leopard e-mail would allow users to create the virtual equivalent of fancy stationery decorated with personal photographs. Modifications to iChat allowed people linked via web cameras to share slide show presentations, playfully distort their pictures or insert fake backdrops.