WASHINGTON, D.C. - Microsoft Chief Executive Steve Ballmer, in his keynote speech at the company's Worldwide Partner Conference this morning, said Windows will have its own slate devices to compete with Apple's iPad .

"Over the course of the next several months you will see a range of Windows 7 based slates that are really quite impressive," Ballmer said at the Verizon Center.

Microsoft puts on the annual conference for its 640,000 partners, who range from consultants to software developer and resellers.

More than 10,000 attendees filled the bottom half of the sports arena, which began with a Glee-style rendition of "I Gotta Feeling," performed not by the "Glee" cast or the Black Eyed Peas, but a group called Mosaic. "Let's give it up ... for Microsoft" was one of the lyrics. Yes, they went there.

Sporting a blue and purple striped polo shirt, Ballmer began his speech with a soccer-style chant of "Oh cloud."

He spent much of his speech recapping his thoughts on cloud computing, similar to a speech he made at the University of Washington earlier this year. Microsoft wants its partners to build more software in the cloud on Microsoft's platform.

"If you want to move to the cloud and want to take advantage of one of the most fantastic waves of interested investments that corporate IT has ever made, there is nobody better to bet on than Microsoft," Ballmer said.

Also interesting, Ballmer again acknowledged problems with Windows Mobile while talking up the coming Windows Phone 7 mobile operating system.

"We missed a generation with Windows Mobile," he said. "We really did miss almost a release cycle.

Returning to speeches. Microsoft executives Bob Muglia, Stephen Elop and Tami Reller coming up.

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