More than 115 CEOs from companies in 26 countries representing more than $3 trillion in annual sales and 10 million employees were invited to a discussion between Charlie Rose and Thomas Friedman, whose new book, "Hot, Flat and Crowded" is due out this summer.

The venue shifts to Redmond this morning where Gates was expected to deliver a keynote address to the influential crowd, which includes Jack and Suzy Welch, Warren Buffett and others. Microsoft is shy about releasing individual company and CEO names, but says that there are representative from most major industries.

Gates' speech, scheduled to begin at 8:30 a.m., Pacific Time, can be viewed live, on the Web.

He will focus on "the next wave of business productivity and the continual challenge of innovation," said Kim Stocks, director of corporate public relations.

A highlight will be the demonstration of a rarely seen prototype technology called Touch Wall, Stocks said. She described it as similar to Microsoft Surface -- the company's tabletop, motion- and object-sensing computer -- only vertical. It sounds like something my colleague Brier Dudley spotted at Microsoft's "Demo Fest" earlier this year. Stocks said the computer Tom Cruise's character uses in the 2002 Steven Spielberg future crime thriller "Minority Report" is another good point of reference.

On Tuesday, I talked with Stephen Elop, the new president of the Microsoft Business Division, which includes the Office Labs research group that came up with Touch Wall.

Elop said Touch Wall is an example of Microsoft's push toward natural user interfaces, such as speech, vision, touch and gestures -- a sweet spot for Gates. This prototype allows a user to manipulate digital objects -- documents, video, photos, vector graphics -- on a wall display. For business purposes, one can give a PowerPoint presentation "not as a series of discreet slides, but as a network of content you can navigate through on your wall and on the PC," Elop said.

Explaining the new product research group behind Touch Wall, Elop said, "Office Labs was created to give the team broadly some flexibility to make sure that we're not just thinking about the next couple of releases, but we're thinking well out there and doing some directional work."

It's an example of how Microsoft seeks to sustain innovation within the company, which is expected to be another theme of Gates' speech, Stocks said.

Other highlights of the CEO Summit, which continues through Thursday, include dinner at the Gates residence, a yacht excursion and a daylong tour of the region for CEO spouses, which in one past year included a visit to Dale Chihuly's studios.

Gates, who is hanging up his full-time Microsoft job this summer, has committed to participate in the 2009 CEO Summit, Stocks said, though exact details have not been ironed out.