A Chinese court has jailed four people for spreading their bootleg Tomato Garden version of Microsoft's Windows XP program, in what the Xinhua news agency called the nation's biggest software piracy case.

Hong Lei, the creator of the downloadable Tomato Garden Windows XP software, was jailed for three and a half years on Thursday by a court in Suzhou in eastern China, Xinhua reported, citing local media.

One of his accomplices received the same prison term and two received two years each.

Hong created the Tomato Garden version of the Windows XP, which crippled the program's authentication and certification barriers, said Xinhua, allowing users unrestricted access to the popular Microsoft software.

Millions of Internet users then had free access to the software on a website, tomatolei.com, which made its earnings from advertisements on the site, it said.

Beijing has publicized court verdicts such as this to show anxious businesses and governments, especially Washington, it is serious about stamping out widespread piracy of copyrighted and patented products, especially films, music and software.

Not everyone has been persuaded.

China's efforts to stop intellectual property theft have been weak and ineffective -- heavy on tough talk but light on implementation, U.S. Congressman Howard Berman of California, who has been visiting Beijing, said in a statement issued by his office.

Hundreds of websites provide downloads and links to pirated movies, recordings and games.

The Tomato Garden website was set up in 2004.

In June last year, the Business Software Alliance -- a business coalition campaigning against commercial piracy -- complained to Chinese authorities, and Hong and his colleagues were arrested later in the year.

The report did not say whether they intended to appeal.

(Reporting by Chris Buckley; Editing by Ken Wills)