National Estuarine Reserve System Act of 2003

National Estuarine Reserve System Act of 2003 - Amends the Coastal Zone Management Act of 1972 to rename the National Estuarine Research Reserve System the National Estuarine Reserve System, and designates existing sanctuaries as part of the System. Authorizes the Secretary of Commerce to designate additional areas as part of the System and specifies requirements for such. Authorizes the Secretary to: (1) contract with an organization to solicit donations to carry out projects; and (2) accept such donations of funds and services.