LOS ANGELES -- Ray Ozzie, Microsoft's chief software architect, talked up cloud computing this morning in his opening keynote at Microsoft's Professional Developers Conference this morning.

Ozzie announced that the Microsoft cloud, Windows Azure, will light up for customers on Jan. 1. The first month will be free and the meter will start ticking for customers on Feb. 1.

The vision, as he said last year here, is "three screens and a cloud." The three screens are the mobile phone, the PC and the television, all connected by the cloud. The cloud consists of applications and software served up through the Internet browser. Most consumers are already using the cloud, whether it be Gmail, iTunes, online flight booking or Web banking. The larger opportunity in cloud computing is for businesses, which can migrate their computing from software installed on PCs and internal servers to the cloud -- servers run by Microsoft.

"We at Microsoft have but one strategy and that is to focus on leverage and seamelessness across everything we do," Ozzie said. "Across the PC, phone, TV , Web and cloud, across our many platforms, across products serving both consumers and businesses."

Windows Azure will be only as successful as the number, diversity and depth of applications developers build for it, and the goal here was to attract as many as possible. Microsoft is competing in the cloud with, among others, Google, Yahoo, Amazon.com and Salesforce.com. Ozzie said in his keynote that "tens of thousands" of developers participated in the technical preview.

He also invited customers to come on stage and via satellite to talk about what they are building in the Microsoft cloud, including these cases:

• WordPress is using Windows Azure, which takes away the stress of managing unexpected massive traffic, as in a situation where Perez Hilton links to a blog item that dries a bunch of hits to your blog.

• ICanHazCheezburger, famous for funny cat photos, is launching a new humor site featuring funny signs, www.oddlyspecific.com on Windows Azure.
  
• Domino's Pizza (via video) is using the Microsoft cloud to manage its ordering system, key to managing the pizza peak on Super Bowl Sunday.


• The White House (via satellite) is building apps off federal databases for the public. NASA is holding a "Be a Martian" competition for anyone who wants to build a cloud app based on Mars Pathfinder images. A less happy moment for Microsoft was when Vivek Kundra, chief information officer for Obama, showed off a Career Finder mobile app on an iPhone.

A project code-named "Dallas" will allow developers to access public and private data for pay via the Microsoft data marketplace called Pinpoint, including Associated Press stories (private), NASA images (public), National Geographic media and more. There may be a lot of potential here for innovative applications.

For an archive of my Tweets from the session, check out my Twitter posts between 8:30 a.m. and 10:30 a.m.

Other highlights:

• Bob Muglia, president of the Server and Tools business, did a video on the cloud with him as Life Coach helping a man dressed as a cloud with an identity crisis. I think we can all relate: What's a private cloud? Public cloud? Hosted cloud? It ended with Muglia, jumping around like Microsoft Chief Executive Steve Ballmer, shouting, "Soar, cloud, soar!"


• Steven Sinofsky, president of the Windows business, will take the stage at Wednesday's morning keynote. I will livetweet that keynote at www.twitter.com/sharonpianchan/.


• Expect lots more details on developing for Windows phones, probably Windows Mobile 7.0, at the Mix conference next year.


• Muglia also showed off Project Sydney, a development platform for Windows Azure that I don't quite have a grasp on yet. Microsoft built its online auction for the annual employee charitable giving campaign on Sydney, and in the demo Muglia showed, a 16-inch chainsaw was going for $1,000.

Here is Microsoft's press release on the keynote.