Targeting Homeland Security Resources Effectively Against Terrorism Act of 2004 (THREAT Act) - Directs the Secretary of Homeland Security to carry out a program under which the Secretary awards grants, from amounts made available for discretionary grants for use in high-threat, high-density urban areas, to not more than 15 areas after considering the population, presence of critical infrastructure, and credibility of the threat for an area. Requires amounts awarded to be disbursed directly to local governments.