Middle Class Tax Relief Act of 2006 - Amends the Internal Revenue Code to: (1) allow individual taxpayers with adjusted gross incomes of less than $75,000 ($150,000 for joint returns) a tax credit for 10% of their income tax; (2) eliminate income taxes for individual taxpayers with adjusted gross incomes of less than $12,500 ($25,000 for joint returns); (3) double the child tax credit for individual taxpayers with adjusted gross incomes of less than $75,000 ($150,000 for joint returns); (4) eliminate the alternative minimum tax in 2007 for certain individual taxpayers; and (5) impose an income tax surtax on individual taxpayers with adjusted gross incomes of over $500,000 ($1 million for joint returns).