Microsoft CEO Steve Ballmer speaks at the launch of the company's Microsoft 365 cloud service in New York, June 28, 2011. [Photo/Agencies]

SEATTLE - Microsoft Corp made its biggest move into the mobile, Internet-accessible world of "cloud" computing on Tuesday, taking the wraps off a revamped online version of its hugely profitable Office software suite.

The world's largest software company is heaving its two-decade old set of applications -- including Outlook email, Excel spreadsheets and SharePoint collaboration tools -- into an online format so that customers can use them on a variety of devices from wherever they can get an Internet connection.

It wants to push back against Google Inc, which has stolen a small but worrying percentage of corporate customers with Google Apps -- a cheaper, Web-only alternative that removes the need for companies to spend time on installing software or managing servers.

Chief Executive Steve Ballmer presented the overhauled and updated set of offerings -- collectively called Office 365 -- at an event in New York City on Tuesday morning, stressing that online versions and built-in conferencing tools can save users money, especially small and medium-sized businesses.

The full launch of Office 365, which has been in beta testing since last autumn, spices up the lively competition with Google for new users.

"While Office 365 does put Microsoft in mortal combat with Google, it is not really an existential threat for Google since Microsoft is essentially validating the model that Google pioneered with Google Apps," said Matt Cain, an analyst at tech research firm Gartner. "I would expect that Office 365 actually heightens interest in Google Apps."

Microsoft shares were up 2.4 percent on Tuesday afternoon, following a 3.7 percent jump the day before, partly buoyed by hopes that the company can ultimately boost profits by extending its software dominance to the growing cloud sector.

Microsoft has offered online versions of some Office programs -- chiefly Outlook email -- for its corporate customers for several years, and last year rolled out free versions for individual home users.

"The biggest thing I like about it is that it takes the need to manage servers away and puts it in someone else's hands," said Kevin Lisota, CEO of Seattle real estate startup Findwell, which has five employees and has been using the test version of the product.

"It takes our email and team Internet sites and basically makes that Microsoft's problem so I don't have to worry about that," said Lisota, who was invited by Microsoft to an Office 365 launch event at its headquarters near Seattle.