The world's most popular office suite and one of Microsoft's biggest sources of revenue is about to get a refresh. As the company rolls out an invitation-only preview of Office 2010, details are beginning to surface about what Redmond has in store for desktop productivity. The most notable change, which Microsoft is not offering to those participating in the preview yet, will be the addition of web-based versions of its software.

No doubt in a response to Google and other vendors, 2010 will be the first Microsoft Office suite designed with web integration fully in mind. The three biggest browsers (IE, Firefox and Safari) are all known to work with Microsoft's web-based versions of Word, Excel, PowerPoint and more. The online suite will be available as a free part of Windows Live next year, but Microsoft hasn't decided whether they will include advertising.

In a similar move to Windows 7, Microsoft has said that the desktop counterpart will largely focus on improving what Office 2007 already offers without re-imagining the entire suite. If you happen to be participating in the technical preview, let us know what you think of the suite. The real test will come later in the year, when a tech preview web apps become available. Even if both Google and Microsoft are “ahead of the market” on demand of web-based apps, it's clear that is where the Office is headed: the browser.