From the L.A. Times:

Wealthy U.S. taxpayers, concerned about an Internal Revenue Service crackdown on the use of secret overseas bank accounts as tax havens, are rushing to meet a Thursday deadline to disclose those accounts or face possible criminal prosecution.

The concern was triggered this summer when Switzerland's largest bank, caught up in an international tax evasion dispute, said it would disclose the names of more than 4,000 of its U.S. account holders.

The decision shattered a long-held belief that Swiss banks would guard the identities of its American customers as carefully as they did their money, and it raised concern that other international tax havens might be next.

Under an amnesty program, the IRS is allowing taxpayers to avoid prosecution for having failed to report their overseas accounts. As a result, tax attorneys across the nation have been besieged by wealthy clients who are lining up to apply even though they will still face big financial penalties. [...]

"It's crazy busy," said Pasadena tax attorney Phil Hodgen, who for a brief period in September stopped accepting new clients because he was overwhelmed with amnesty requests. "These people are calling, saying, 'I can't sleep at night.' "

Some 3,000 U.S. residents have voluntarily disclosed their foreign bank accounts to the IRS this year, compared to fewer than 100 in 2008, said one U.S. government official who asked not to be identified.