The FBI said one of the occasions was in Nashville, Tenn., where he requested to stay in the hotel room next to Andrews. Barrett is suspected to have taken videos from his cell phone through the peephole in the reporter's door. According to the criminal complaint, the length of the peephole in the door was shortened to make it easier to remove it quickly and easily without making much noise.
The second videotaping incident took place in a Milwaukee hotel, authorities said, though Barrett never checked in at the hotel there. Officials allege the peephole on the door of Andrews' room was tampered with in a similar style to Andrews' room in the Nashville hotel.
The suspect then attempted to sell, via e-mail, the grainy videos to entertainment Web site TMZ.com, where an employee notified Andrews' attorney. ESPN said the e-mails were traced back to Barrett.
TMZ, which is based in Los Angeles, did not post the videos, but they did surface across the Internet on adult Web sites.
Barrett faces up to five years in prison if he is convicted of interstate stalking.
Andrews' lawyers say the victim, who has been working closely with the United States Attorney, FBI, local authorities and a private investigation firm, is greatly relieved about the arrest.
"I think she's probably sleeping more soundly tonight than she has since these videos surfaced," said Andrews' attorney, Marshall Grossman, of his client.
Investigators say Andrews suffered from anxiety and was always fearful that a stalker might be watching her. She even called 911 when the paparazzi camped outside her Atlanta home in July after the videos had surfaced.
"My last name is Andrews. I'm all over the news right now," she told the 911 operator. "I'm the girl that was videotaped without her knowing, without her clothes on in the hotel. ... They're looking at me through my window."
When the operator asked if she was OK, Andrews responded, "I did nothing wrong, and I'm being treated like ... Britney Spears."
Andrews has worked as a sideline reporter for ESPN's college football and college basketball broadcasts since 2004. The former sports dancer had amassed a large fan following even before the nude videotapes surfaced.
Some Web sites called her "Erin Pageviews" because of her popularity on the Internet, and Playboy magazine named her "sexiest sportscaster" in 2008 and 2009.
The videotapes caused a sensation on the Web, and Andrews topped Google's list of most searched terms for nearly a week in July, when the sportscaster found out about the incident.
Andrews, who returned to work in September, told talk show host Oprah Winfrey she was horrified when she saw her nude videos posted on the Internet, and she feared her career was over.
"I opened up the computer and could feel my heart pounding," Andrews told Winfrey.
"I kept screaming, 'I'm done. My career is over. I'm done. Get it off. Get it off the Internet,'" said Andrews, recalling the phone call to her father when she first spotted the videos. "They thought I was physically injured, [that's] how bad I was screaming."
ABC News' Justin Weaver, Todd Conner and Russell Goldman contributed to this report.