http://www.irs.gov/newsroom/article/0,,id=179181,00.html
Taxpayer Identification Numbers
Q. I file using an individual taxpayer identification number (ITIN). Can I still get a stimulus payment?
A: No. The law does not allow stimulus payments to people who file a return using an ITIN. A taxpayer must have a valid Social Security Number to qualify for the stimulus payment. If married filing jointly, both taxpayers must have a valid Social Security Number. And children must have valid Social Security Numbers to be eligible as qualifying children.
Q. I have an ITIN, but my spouse has a valid Social Security number. Can we get a payment?
A. If you and your spouse file a joint return, you will not get a stimulus payment. If your spouse files a separate return, your spouse may qualify for a payment, based on his or her income deductions and credits.
Q. If I have a valid Social Security Number and my child has an ITIN, do I get extra money for the child?
A. No. To qualify for the extra credit for qualifying children, not only do the taxpayer and spouse, if filing jointly, need valid Social Security Numbers, but the qualifying child must also have a valid Social Security Number.