Two men have been sentenced to more than five years in prison for their part in sending millions of pornographic spam messages, marking the conclusion of the first major case under the 2003 federal CAN-SPAM anti-spam law.

Jeffrey Kilbride, 41, and James Schaffer, 41, were convicted in June by a federal jury in Phoenix on eight counts that included violations of the CAN-SPAM Act, which bans the use of falsified e-mail headers and the spoofing of domain names. Their case was the first to include CAN-SPAM charges.

On Friday, US District Judge David Campbell sentenced Kilbride to 72 months in prison, and Schaffer to 63 months.

According to prosecutors, the two men, along with three co-conspirators, sent millions of unsolicited messages advertising hard-core pornographic websites that included pornographic images visible to anyone who simply opened the message. In late 2003, after the CAN-SPAM Act was passed, Kilbride and Schaffer tried to mask their US-based operation by routing traffic through Dutch servers and spoofing the domain posing in the From: field of outbound messages.

In just over a year, the two made more than £500,000 in commissions from the websites they hawked.

Campbell also fined the pair $100,000 each, ordered them to pay $77,500 in restitution to AOL and required them to forfeit their ill-gotten gains.

The three others involved in the spam ring included Jennifer Clason, 32, of Tempe; Andrew Ellifson, 31, of Scottsdale; and Kirk Rogers, 43, of Manhattan Beach. All pleaded guilty earlier and testified against Kilbride and Schaffer.

Clason gained some notoriety after her guilty plea when researchers discovered in March 2006 that she was running a website aimed at work-at-home mothers. Although the site, MommyJobs.com, had no direct links to pornography, it did advertise get-rich-quick schemes, another staple of spammers.

When she announced on MommyJobs.com that she was stepping away from the site, Clason claimed that she had been victimised. "Apparently this guy that I had trusted for five years had lied to me," she wrote on a MommyJobs.com forum last year. "Not only was his spam operation illegal, but he was also doing other shady stuff that I had no knowledge of like money laundering!!"

Clason's sentencing has been repeatedly postponed; it is now scheduled for 26 November.