Homeland Security Information Sharing and Analysis Enhancement Act of 2004

Homeland Security Information Sharing and Analysis Enhancement Act of 2004 - Amends the Homeland Security Act of 2002 to provide for the establishment of an interagency Homeland Security Information Requirements Board to oversee the process for establishing homeland security requirements and collection management for all terrorism-related and other homeland security information collected within the United States.

Includes among the responsibilities of the Department of Homeland Security's (DHS) Under Secretary for Information Analysis and Infrastructure Protection to: (1) ensure the simultaneous dissemination of data and information regarding communications and information technology infrastructure to appropriate personnel with maximum flexibility and speed; (2) coordinate the issuance of homeland security advisories and advice from other Federal agencies to State and local government, the private sector, other entities, and the public; and (3) administer a homeland security information network.

Authorizes the Secretary to provide DHS personnel access to threat and vulnerability information required to discharge their duties.

Directs the Secretary, where credible information indicates a potential terrorist threat that cannot be limited to one or more States, regions, critical infrastructure sectors, activities, or events, to use the Homeland Security Advisory System to inform the public of the threat, convey risk information, and provide specific unclassified warning information and advice about protective measures.

Limits the dissemination of threat information without the Secretary's prior approval.

Authorizes assignment of DHS personnel to the Terrorist Threat Integration Center.