"The tax credit, which expires Jan. 1, was designed to increase take-home pay by about $8 a week through new tax withholding tables. The credit was capped at $400 for individuals and $800 for married couples filing jointly."

"WASHINGTON (AP) –– About 13.4 million taxpayers may be getting unexpected tax bills because they were awarded too much money under President Barack Obama's Making Work Pay tax credit, a government audit said Thursday."

http://finance.yahoo.com/news/13M-get-unexpected-tax-bill-apf-514145692.html?x=0