By Sam Oliver

Published: 10:00 AM EST

Microsoft on Monday announced plans to begin widespread testing of a new version of its market-leading productivity suite for Windows PCs that will tie into a series of new Web-based Office applications similar to those offered by rival Google.

Presenting at its Worldwide Partner Conference 2009, the Redmond, Wash.-based software giant said it will soon invite tens of thousands of customers to start testing Microsoft Office 2010, which features broadcast and video editing in PowerPoint, new data visualization capabilities in Excel, and co-authoring in Word.

As part of the announcement, Microsoft also said it plans to take Office online, with a new series of free Office Web applications aimed at combating the encroachment on its space by arch rival Google, whose online document and spreadsheet applications have been growing in popularity.

The ad-supported web suite will reportedly be available to more than 400 million Windows Live consumers at no cost. It will also be accessible on-premises for all Office volume licensing customers and via Microsoft Online Services, where customers will be able to purchase a subscription as part of a hosted offering.

"Office Web Applications, the online companion to Word, Excel, PowerPoint and OneNote applications, allow you to access documents from anywhere. You can even simultaneously share and work on documents with others online," Microsoft says on its Office 2010 Technical Preview site. "View documents across PCs, mobile phones, and the Web without compromising document fidelity. Create new documents and do basic editing using the familiar Office interface."

Microsoft, which also announced that it is streamlining the number of Office editions from eight to five, said customers will be able to purchase the new suite sometime in the first half of next year. The company made no announcements related to future versions of Office for the Mac, which will more than likely also tie into the new Web-based suite once it materializes.