Insular Areas Tax Credit Guarantee Act of 2003

Insular Areas Tax Credit Guarantee Act of 2003 - Amends the Internal Revenue Code, with respect to the coordination of United States and certain possession individual income taxes, to direct the United States to pay to: (1) any possession whose income tax laws mirror the Code an amount equal to the refundable portions of the child care and earned income credits paid by such possession; and (2) Guam, American Samoa, the Virgin Islands, or the Northern Mariana Islands, the amount of taxes withheld from Federal personnel who are temporarily assigned or deployed in such possession for more that 30 days in a calendar year.