A Seattle man, who we wrote about in September after he was charged with downloading file-sharing programs to victims’ computers to steal their identities, pleaded guilty Monday in federal court.

Gregory Kopiloff, 35, pleaded guilty to mail fraud, accessing a protected computer without authorization to further fraud and aggravated identity theft. He faces up to 20 years in prison when he is sentenced, scheduled for Jan. 28.

Authorities said his arrest may be the first publicized instance in which someone ripped off identities through programs such as Limewire and Soulseek.

But it certainly was not the first time this year that we’ve heard about data being stolen through peer-to-peer (P2P) software, although those instances were due to accidental disclosure.

According to the indictment, Kopiloff bought more than $73,000 in products in the process of defrauding more than 83 victims from March 2005 to this past August.

Some experts, including Gartner’s John Pescatore, are predicting 2008 may bring a slew of P2P data breaches, fueled by employee use of the file-sharing programs.