Federal Prison Bureau Nonviolent Offender Relief Act of 2003 - Amends the Federal criminal code to direct the Bureau of Prisons, pursuant to a good time policy, to release a prisoner who has served one half or more of his or her term of imprisonment if that prisoner: (1) has attained age 45; (2) has never been convicted of a crime of violence; and (3) has not engaged in any violation, involving violent conduct, of institutional disciplinary regulations.