Two years after announcing a somewhat vague software-distribution partnership, Google Inc. (GOOG) and Sun Microsystems Inc. (SUNW) have clarified their tactics for jointly attacking Microsoft Corp. (MSFT) and its ubiquitous Office software.

Over the weekend, Google quietly began including Sun's StarOffice suite of word processing, spreadsheets and other workplace-oriented programs for free as part of the Google Pack download.

The download package is part of Google's efforts to expand beyond Web search and control more of users' computing experience online and offline.

• Click here for's Personal Technology Center.

It already includes Firefox, the No. 2 Web browser behind Microsoft's Internet Explorer, and RealNetworks Inc.'s (RNWK) RealPlayer, a key rival to Microsoft's own media player.

By adding Sun's software, Google is giving a valuable endorsement to a server and software maker that saw demand for its products collapse after the dot-com bust and has struggled to return to sustained profitability ever since.

StarOffice is Sun's commercial version of the freely distributed OpenOffice suite, which also was developed by Sun and has been downloaded about 100 million times.

StarOffice typically costs $70 to download but is being distributed by Google for free. It has more features than OpenOffice and typically includes technical support from Sun, though the free Google version won't.

Both companies declined to comment on their financial arrangement.

Rich Green, Sun's executive vice president of software, said Wednesday that Sun has also added Internet search capabilities to all of its StarOffice products.

That will allow users, for example, to highlight terms in a word processing document and search immediately for those terms online — through Google, of course.

"It's a paradigm shift," Green said in an interview. "It brings together office productivity, networking and search into one offering."

The partnership announced in October 2005 between Mountain View-based Google and Santa-Clara based Sun had been light on details.

The companies only said then that users who download Sun's Java software, which is needed to run a variety of Web applications, would also have the option of downloading Google's search toolbar, and that they would work closely in the future to promote and distribute each other's software.

Google said in a statement Wednesday that the company believes "users will benefit from access to a free, full-featured office suite for the desktop. And we've also always believed that users should have choice in their online and PC experience."