A Boston Federal judge is to begin hearing arguments today accusing Facebook founder Mark Zuckerberg of breach of contract, copyright infringement and fraud.

Fellow Harvard students Divya Narendra, Cameron Winklevoss and Tyler Winklevoss have accused Zuckerberg of using proprietary source code which they claim to have developed with him to create Facebook.

They claim that Zuckerberg was a member of their development team working on a similar project, which was launched in 2004 under the name ConnectU, during which time he allegedly stole their idea and the source code. 

The three plaintiffs originally filed the suit in September 2004, but it was dismissed on a technicality. The trio then refiled, and the case finally gets underway today.

The plaintiffs claim that they first found out about Zuckerberg's project in a Harvard newsletter, at which point they removed him from the ConnectU project. But by then he had allegedly taken the material he wanted.

The suit is calling for a complete shutdown of Facebook as well as payment for damages and a transfer of Zuckerberg's assets.

Facebook has already filed a countersuit alleging defamation.

Users have flocked to Facebook in their millions, making it the second most popular social networking site after MySpace. ConnectU has managed to garner around 100,000 subscribers.

At least one person connected to the social networking phenomenon seems untroubled by the case. Gideon Yu, former YouTube chief financial officer, has just accepted the job of chief financial officer at Facebook. 

Yu's appointment fuels further speculation that Facebook is heading for an initial public offering on the Nasdaq stock exchange, after turning down takeover bids from Yahoo and Google. 

Facebook has 32 million users and has been valued as high as $10bn.