The Earned Income Tax Credit
The Earned Income Tax Credit, EITC or EIC, is a benefit for working people with low to moderate income. To qualify, you must meet certain requirements and file a tax return, even if you do not owe any tax or are not required to file. EITC reduces the amount of tax you owe and may give you a refund.
IRS Site for EITC Information - Very User Friendly Site