Social Security Number Online Protection Act of 2006 - Amends the federal criminal code to prohibit a state or local government from displaying to the general public on the Internet the last four digits of any social security number. Imposes a fine of up to $5,000 a day on any state or local government that has a policy or practice of substantial noncompliance with the requirements of this Act. Authorizes the Attorney General to bring a civil action against a state, local government, or officer, employee, or contractor of such state or local government to enforce compliance with this Act.

Directs the Attorney General to award grants to states and local governments for removing or redacting the last four digits of social security numbers from forms and records of their executive, legislative, and judicial agencies which are currently displayed on the Internet.