Arizona- Jeffrey Kilbride and James Schaffer started their spam business operation in 2003 after buying lists of email addresses, with each address representing a payout if its owner joined the X-rated site.

The two men are the first subjects to be prosecuted under US anti-spam law for launching a sustained attack, which caused 1.5 million complaints from people flooded with links to porn.

They were convicted on Friday of charges including conspiracy, money laundering, fraud and transportation of obscene material after a three-week trial in Arizona.

But Kilbride was handed down a longer sentence of 72 months, because he tried to prevent a witness testifying at the trial, Department of Justice officials said.

Both men were charged under the Controlling the Assault of Non-solicited Pornography and Marketing (CAN-SPAM) Act by sending spam messages using bogus headers and domains.

Federal prosecutors suggested the men went to great lengths to avoid detection: after CAN-SPAM took effect in 2003, they relocated their operation abroad, remotely accessing servers located in Amsterdam.

For their finances, the pair used bank accounts in Mauritius and the Isle of Man to receive and funnel the proceeds from their operation, which amassed $2m (�1m) in four years.

And on their e-mails, the name of a fake internet domain name was listed, seemingly created by staff at Shell Corporation in The Republic Mauritius.

Despite making it appear their business was located Europe, the men were e-mailing their victims from Phoenix, with help from three other named co-conspirators.

Kilbride and Schaffer were fined $100,000 and ordered to pay $77,500 in restitution to AOL. A federal judge also ordered them to jointly forfeit $1.1 million, their estimated haul from the operation.