Border Infrastructure and Technology Modernization Act of 2003

Border Infrastructure and Technology Modernization Act - Directs the Under Secretary for Border and Transportation Security of the Department of Homeland Security to: (1) make specified personnel increases in the Department of Homeland Security's Bureaus of Immigration and Customs Enforcement, and Customs and Border Protection, respectively; (2) prepare an annual National Land Border Security Plan, which shall include a vulnerability assessment of each port of entry on the northern or southern border, and may provide for port security coordinators; and (3) carry out a three-to-five-site port of entry demonstration program.

Directs the Administrator of General Services to make annual updates to the Port of Entry Infrastructure Assessment Study.

Directs the Commissioner of the Bureau of Customs and Border Protection to: (1) develop an expansion plan for the Customs-Trade Partnership Against Terrorism programs along the northern and southern borders, including the Business Anti-Smuggling Coalition, the Carrier Initiative Program, the Americas Counter Smuggling Initiative, the Container Security Initiative, the Free and Secure Trade Initiative, and other Industry Partnership programs; (2) establish a Partnership demonstration program along the southern border; and (3) establish a demonstration program for a cooperative trade security system with respect to entities (maquiladora) in Mexico that assemble and produce goods from imported parts for export to the United States.

Authorizes specified appropriations.