From IRS.gov:
For tax-year 2009, Congress raised the alternative minimum tax exemption to the following levels:
- $70,950 for a married couple filing a joint return and qualifying widows and widowers, up from $69,950 in 2008
- $35,475 for a married person filing separately, up from $34,975
- $46,700 for singles and heads of household, up from $46,200
Under current law, these exemption amounts will drop to $45,000, $22,500 and $33,750, respectively, in 2010. Form 6251 and the AMT calculator provide more information.