Depending on your AGI (Adjusted Gross Income – that is the bottom line of the first page of your personal Form 1040), you may be eligible for a $400 credit ($800 if married filing joint).
For 2009, if your filing status is Single, Head of Household or Married filing separate, the phase out of the credit begins at $75,000 and ends at $95,000. That means if you made less than $75k, you get the whole $400. If you made $95k, you get none.
If your filing status if Married Filing Joint, the phase out begins at $150k and ends at $190k.
We do not know at this time whether the AGI restrictions will be exactly the same for 2010.
You MAY have already received up to $250 of the credit if you are a recipient of Social Security, SSI, railroad retirement, Veteran’s disability compensation or pension benefits.