Google unveiled a new Web-site publishing tool for office workers late Wednesday, taking aim at rival Microsoft in the corporate tools arena.

The Mountain View-based company debuted a free service designed for workers looking to share information with other people working in the same company or attending the same class in school.

Google Sites, as the new site publishing service is known, is a scaled back version of JotSpot, an Web creating tool edit service for organizations and individuals to set up and edit Web sites that Google had acquired 16 months ago for undisclosed terms.

All sites created on the service will run on one of Google's computers.

The tools are the latest addition of Google applications that serve as alternatives to Microsoft products.

While Microsoft's programs typically are installed on individual computers, Google keeps its application on its own machines so users can access them from anywhere with an Internet connection.

By gradually introducing free versions of word processing, spreadsheet, and calendaring programs over the past two years, Google has been threatening to siphon revenue away from Microsoft, which makes most of its money from software sales.

Google Sites similar to Microsoft's SharePoint collaboration software, which workers inside an organization share documents and maintain calendars on secure Web sites.