Call the credit reporting companies:
Exuifax - 1-888-766-0008
Experian - 1 888 397 3742
Social Security - 1-800-772-1213 <---- you need to call them right now and tell them what is going on. They will issue a fraud alert on your SS# and make it difficult for any new lines of credit to be opened without your personal consent.
Lots of info:
http://www.consumer.gov/idtheft/