Here's a news release from the IRS about this tax credit:

More than 160,000 California taxpayers so far have taken advantage of the first-time homebuyer federal tax credit that provides up to $8,000 to those purchasing a home.
But time is running out to qualify. Here are 10 things the IRS wants you to know about this valuable credit:

1. To be considered a first-time homebuyer, you — and your spouse if you are married — must not have jointly or separately owned another principal residence during the three years prior to the date of purchase.

2. You cannot claim the credit before there is a completed sale and purchase of the residence. The sale and purchase are generally completed at the time of closing on the purchase.

3. To qualify for the credit, the completed purchase must occur before Dec. 1, 2009.

4. The home must be located in the United States.

5. The credit is either 10 percent of the purchase price of the home or $8,000, whichever is less.

6. The amount of the credit begins to phase out for taxpayers whose modified adjusted gross income is more than $75,000 or $150,000 for joint filers.

7. The credit is fully refundable. A homebuyer with no taxable income, who qualifies for the credit, may file for the sole purpose of claiming the credit and receive a refund. The credit will be paid out to eligible taxpayers, even if they owe no tax or the credit is more than the tax owed.

8. The credit is claimed on IRS Form 5405, First-Time Homebuyers Credit.

9. Taxpayers can claim the credit for a qualified 2009 purchase on either their 2008 or 2009 tax return. For those who have filed a 2008 return, a Form 1040X, Amended U.S. Individual Income Tax Return can be filed in order to get a refund in 2009.

10. The credit for qualified 2009 purchases does not have to be repaid, as long as the home remains your main home for 36 months after the purchase date.

Qualified taxpayers who have been considering a main home purchase may find extra incentive from this tax credit to buy now so they can complete the purchase before the Dec. 1 deadline. 

For more information on this and other key tax provisions of the American Recovery and Reinvestment Act of 2009, visit the official IRS Web site at www.irs.gov.