Sun is set to announce plans to support OpenOffice, citing a wave of momentum behind the open-source project.

The support, which starts at US$20 per user per year, will be offered to companies that distribute OpenOffice, not to the end-users themselves, according to Mark Herring, senior director of marketing for StarOffice/OpenOffice and Network. "For a lot of distributors, they wanted to distribute OpenOffice and had no option for back-line support," he said.

OpenOffice and StarOffice, Sun's accompanying commercial product, are compatible with Microsoft Office and identical in terms of capabilities, which include word processing, spreadsheets and presentation software. But until now, Sun only supported StarOffice.

Another difference will remain - Sun does not plan to provide indemnification against lawsuits for OpenOffice as it does for StarOffice, Herring said.

Sun's move comes as is being downloaded 1 million times per week, with total downloads to date standing at about 110 million, Herring said.

Out of that number, Sun estimates that "tens of millions" of people are actively using the software, according to Herring. The most recent version is 2.3. Version 2.4 is expected in March and will contain significant new features, according to the OpenOffice website.

"Microsoft Office is still the dominant tool out there - only a fool would deny that," he said. "But [OpenOffice] has had a huge amount of momentum."

Sun believes the average OpenOffice user is younger than the average Microsoft Office user, and that download activity in Europe and the US has been greater than in Asian countries, he added.

Developers can create extensions to the core suite. Sun has made a new one for shaving down the size of presentation files, Herring said. The wizard-like tool goes through a file and asks users whether they want to keep or compress the various elements, he said.

Sun plans to provide support for any extensions it creates, according to Herring. As for ones made by third parties, "we would have to work with them on that code on a case-by-case basis," he said.

Sun is also releasing StarOffice 8 Server. Herring described it as a conversion engine that changes 40 document types into PDF files. The server is aimed at enterprises with large stores of legacy documents that aren't archived with an open standard, according to Herring.