While Microsoft considers whether it will release a version of its Office suite as an online service, a California-based startup is giving business users a way to view and share Web-based versions of Office documents through its own hosted service.

EXpresso, based in Palo Alto, offers a hosted application that lets people share and edit Microsoft Office Excel files online without having to e-mail entire document files that must be opened locally. Come September, the company will release a beta of a service that lets people do the same with PowerPoint and Word documents, said George Langan, CEO and president of eXpresso.

EXpresso has worked closely with Microsoft to ensure compatibility between native Office files and their online versions, he said.

The company even is collaborating with the software vendor to make its service available directly through SharePoint Server, Microsoft's portal and collaboration software. This will allow business users to view and edit files available on a company's SharePoint-driven portal within the eXpresso service, precluding the need to get behind a company's firewall to access the files, Langan said.

The integrated SharePoint service should be available by the end of the year, about the same time the eXpresso service for Word and PowerPoint files also should be in full release, he added.

Microsoft's Office suite remains the most widely used productivity software in the world, but it is facing competition from online suites such as Google Docs that give free, Web-based access to basic productivity applications.

Microsoft has been offering more and more of its software in hosted versions, starting a couple of years ago with Exchange Server and recently expanding to offer online versions of SharePoint and the video and audio-conferencing software Office Live Meeting.

However, the company has not unveiled plans to release an online version of its Office suite -- even a basic one -- likely because doing so would cannibalize what is a massive business for the company.

"No one has a bigger embedded user base than Office," Langan said. "They don't want to jeopardize that revenue stream."

Langan pointed out technical problems with putting a massive application like Office online as another reason Microsoft has not done it so far.

Because of this, he sees eXpresso as a technology-agnostic way for companies that are trying to create cloud-computing environments -- or, for lack of a better term, an entirely Web-based dashboard for user productivity and collaboration applications -- to let business users share files between those different environments.