We are in the middle of paperwork for my Wife and her 2 daughters with an Immigration Attorney. They have resided in the U.S for the last year. Can I claim them on my taxes and if so what paperwork do I need? They have the Canadian of a Social Security Number which I know is not valid here. Any assistance would be appreciated.

You can claim them if they are US resident aliens or residents of either Canada or Mexico. You will need to obtain an Individual Taxpayer Identification Number (ITIN) for each of them - you submit form W-7. For details see: General ITIN Information (http://www.irs.gov/individuals/article/0,,id=222209,00.html)