For those looking for the latest on the housing tax credit, the WSJ has a good summary:
Q: If I buy a new home and live in it, do I also have to sell my old one in order to take advantage of the credit?
This is unclear. The law appears to allow repeat buyers to retain their old home, for which no tax credit was given, while claiming a credit for the new one. What is clear is that if you buy a new home using the credit, you must use it as your principal residence.
Q: What is the definition of “principal residence”?
If you own more than one home, your principal residence is usually the one where you spend most of your time. In determining residence the IRS may also consider where your family lives and your mailing address for bills and correspondence, among other factors.
Q: Can a principal residence be something besides a conventional house?
Yes. A principal residence may also be a condominium, co-op apartment, attached or semi-attached townhouse, or even—if it has eating, sleeping and toilet facilities—a boat, motor home or trailer. Manufactured homes qualify in some states.
Q: I need the credit refund to help make the down payment. What can I do?
There’s no rushing the IRS. But one option is to adjust your current withholding from your paychecks to reflect the fact that you will be taking the credit later. But be careful: If you don’t make the purchase, then you may owe interest and penalties. Consult a tax adviser.
Q: Is it possible to qualify for a credit if I am building a home on a lot I already own?
Yes, according to the National Association of Home Builders. The purchase date is usually considered to be the date of first occupancy, so you would need to move in before July 1, 2010.