Antiterrorism Tools Enhancement Act of 2003

Antiterrorism Tools Enhancement Act of 2003 - Amends the Federal Rules of Criminal Procedure to authorize a magistrate judge, at the request of a Federal law enforcement officer or attorney for the Government, to issue a warrant in an investigation of a Federal crime of terrorism or of specified offenses relating to information concerning such a crime (currently, in an investigation of domestic or international terrorism).

Authorizes the Attorney General, in any investigation concerning a Federal crime of terrorism, to subpoena witnesses, compel the attendance and testimony of witnesses, and require the production of records that he finds relevant or material to the investigation. Provides that the attendance of witnesses and the production of records may be required from any place subject to U.S. jurisdiction at any designated hearing place, except that a witness shall not be required to appear at any hearing more than 500 miles distant from the place where he was served with a subpoena.

Sets forth provisions regarding the service of subpoenas, enforcement of subpoenas, a nondisclosure requirement and its enforcement (if the Attorney General certifies that otherwise there may result a danger to national security), termination of such requirement, and judicial review.

Immunizes from civil liability any person who in good faith produces the records or items requested in a subpoena. Directs the Attorney General to issue guidelines to ensure the effective implementation of this Act.