Facebook founder Mark Zuckerberg will defend against copyright-infringement allegations today, as his former Harvard classmates claim he stole the idea for the social-networking site.

Brothers Cameron and Tyler Winklevoss, and Divya Narendra say Facebook was their idea and are asking a judge to give them all of the assets and ownership rights to the site, which could be worth several billion dollars.

In 2002, they say, they began developing a business plan for a Web site originally called the Harvard Connection and later renamed ConnectU. The next year they engaged Mark Zuckerberg to complete the computer program software and other work for the Web site. But they accuse Zuckerberg of using their ideas and code to launch Facebook before finishing the work he promised to do for ConnectU and claiming the idea as his own.

"Zuckerberg knowingly made false statement of intention when he agreed to create, complete, and/or provide source code to . . . the Harvard Connection website," the complaint states. "Zuckerberg never intended to provide the code and instead intended to breach his promise . . . and intended to steal the idea for the Harvard Connection website, and in fact he did so."

The court battle began in 2004, but the original complaint was dismissed - reportedly because of a technicality - on 28 March. The legal merits of the case were never ruled upon, and Zuckerberg's former classmates refiled their complaint in US District Court in Boston, where tomorrow's hearing will be held to consider Zuckerberg's motions to dismiss.

"Only one of [the students] had an idea significant enough to build a great company. That one person was Mark Zuckerberg, the founder of the popular website, www.facebook.com," Zuckerberg's lawyers state in one of the motions.

Four of Zuckerberg's business partners are also listed as defendants, along with Facebook itself.