Garrett Bauer made tens of millions of dollars illegally trading on stock tips. Lately, he has been seeking tips of another kind—about getting along in federal prison.

Former inmates have advised him not to raise his fists if another prisoner tries to provoke a fight. He should curl his body in a ball on the floor instead. And he has been told not to run up debts or take part in spats about what to watch on television.

"I'm going to be new, so you don't want to stick your two cents in," says Mr. Bauer, a slight, 44-year-old felon who in May is scheduled to be sentenced to as much as 11 years in prison for insider trading.

Advising panicky white-collar criminals on what life is like behind bars is a bull-market business, what with all the arrests on Wall Street for insider trading.

As America's lockups have become more crowded, so has the prison-prep industry, a field built for white-collar criminals with the means to pay for lessons on coping with strip searches and with getting along with a tattooed cellmate named Bubba.