November's 52-page indictment, along with papers filed last week, offer an unusually detailed glimpse into a shadowy world where hackers, often not old enough to vote, brag in online chat groups about their prowess in taking over vast numbers of computers and herding them into large armies of junk mail robots and arsenals that flood Web sites with data until they crash.

Ancheta one-upped his hacking peers by advertising his network of "bots," short for robots, on Internet chat channels.

A Web site Ancheta maintained included a schedule of prices he charged people who wanted to rent out the machines, along with guidelines on how many bots were required to bring down a particular type of Web site.

In July 2004, he told one chat partner he had more than 40,000 machines available, "more than I can handle," according to the indictment. A month later, Ancheta told another person he controlled at least 100,000 bots, and that his network had added another 10,000 machines in a week and a half.

In a three-month span starting in June 2004, Ancheta rented out or sold bots to at least 10 "different nefarious computer users," according to the plea agreement. He pocketed $3,000 in the process by accepting payments through the online PayPal service, prosecutors said.

Starting in August 2004, Ancheta turned to a new, more lucrative method to profit from his botnets, prosecutors said. Working with a juvenile in Boca Raton, Fla., whom prosecutors identified by his Internet nickname "SoBe," Ancheta infected more than 400,000 computers.

Ancheta and SoBe signed up as affiliates in programs maintained by online advertising companies that pay people each time they get a computer user to install software that displays ads and collects information about the sites a user visits.

Prosecutors say Ancheta and SoBe then installed the ad software from the two companies — Gamma Entertainment of Montreal, Quebec, and Loudcash, whose parent company was acquired last year by 180Solutions of Bellevue, Wash. — on the bots they controlled, pocketing more than $58,000 in 13 months.