Prosecutors allege that her actions ultimately caused a 13 year-old girl to commit suicide.
Lori Drew, 49, of O'Fallon, Missouri, was indicted on one count of conspiracy and three counts of accessing protected computers without authorisation to obtain information.
Drew is accused of inflicting emotional distress on the girl who, because of juvenile privacy rules, is referred to in the case as 'MTM'.
The woman is alleged, along with others, to have registered as a member of MySpace under the name 'Josh Evans'.
Drew and her co-conspirators then used the account to contact MTM and begin what the girl believed was an online romance with a 16 year-old boy.
After approximately four weeks of flirtatious communications between 'Josh Evans' and MTM, Drew and her co-conspirators broke off the relationship. Within an hour, MTM had hanged herself in her room. She died the next day.
By these actions, Drew and her co-conspirators violated MySpace's terms of service that prohibit users from using fraudulent registration information, using accounts to obtain personal information about juvenile members, and using MySpace communication services to harass, abuse or harm other members.
"This adult woman allegedly used the internet to target a young teenaged girl with horrendous ramifications," said US Attorney Thomas P. O'Brien.
"After a thorough investigation, we have charged Drew with criminally accessing MySpace and violating rules established to protect young, vulnerable people.
"Any adult who uses the internet or a social gathering website to bully or harass another person, particularly a young teenaged girl, needs to realise that their actions can have serious consequences."
The conspiracy count carries a maximum statutory penalty of five years in federal prison.
Each count of accessing protected computers, each of which alleges that the access was for the purpose of intentionally inflicting emotional distress on MTM, carries a maximum penalty of five years in prison.
Drew will be summoned to appear for an arraignment in a US District Court in Los Angeles in June.
Rebecca Lonergan, a law professor at the University of Southern California, and former federal prosecutor, said: "We are in uncharted waters here. This case is unprecedented, and it is also a very aggressive charging decision."
Drew has denied the charges through her lawyer, claiming that she knew of the MySpace account's existence but did not send any messages. She also alleges that the actions were down to her daughter and a teenaged employee, Ashley Grills.
Grills has since appeared on television claiming that Drew was deeply involved in the bullying, did send messages and deleted information from the false profile.
Officials at MySpace said in a written statement: "MySpace does not tolerate cyber-bullying and is cooperating fully with the US attorney in this matter."
Woman charged over MySpace suicide
By Clement James on May 19, 2008 12:02PM