Kirsch, 22, who had been under house arrest in Philadelphia, surrendered to the U.S. Marshals Service at the federal courthouse about 1:30 p.m. - one day before she was to report for jail.

The move sets the stage for her to plead guilty, probably during the next two weeks, and to show U.S. District Judge Eduardo C. Robreno that she has begun to accept responsibility for her crimes by, in effect, starting a prison sentence early.

"She's going to have to pay the price," said her attorney, Ronald Greenblatt. "And this is part of that price - going to jail."

With Kirsch facing a mandatory sentence of at least two years in prison, he said, "given all the circumstances of the case, it didn't make sense to stay out any longer."

Kirsch, who captivated an international audience when photos of her circulated on the Internet after her arrest, was headed late yesterday to the federal detention center at Seventh and Arch Streets, said Acting Chief Deputy Marshal John Patrignani.

There, Kirsch will find herself in surroundings that are more stark and sterile than her once-luxurious lifestyle.

She is accused, along with her onetime boyfriend, Edward K. Anderton, 25, of stealing credit cards and identification from friends, coworkers and strangers in a bar, and then using the fake IDs to live lavishly, shop well and travel widely.

The two have been dubbed the Bonnie and Clyde of identity theft.

Anderton, a graduate of the University of Pennsylvania, pleaded guilty last month to the charges, and is scheduled to be sentenced next month.

Greenblatt said Kirsch still intended to plead guilty. A date has not been scheduled.

Kirsch's surrender came after a court order was filed stating that she had agreed to "voluntarily surrender" by 2 p.m. today pending a trial or guilty plea in the case.

The surrender was "upon the agreement of the parties," meaning that Assistant U.S. Attorney Louis D. Lappen and Greenblatt agreed that she would go behind bars.

Greenblatt said he had initiated the surrender. "It was completely done on our part," he said.

Last month, Lappen sought to have Kirsch detained for committing new crimes while free on bond - stealing a coworker's credit card and using it at a California drugstore and an Ikea store, taking a bicycle by asking to take it for a test ride and never returning it, and lifting a candle from a store.

But Robreno instead ordered her under house arrest in Philadelphia in the custody of a parent or her grandmother at all times, increased her bond, and told her to stay off the Internet and the phone, and not to engage in any banking or credit transactions.