Montgomery GI Bill Second Chance Act of 2004 - Authorizes certain members of the Armed Forces to make an irrevocable election during October of any year beginning in 2004 to become entitled to basic educational assistance under the Montgomery GI Bill.
Requires a reduction in basic pay of those members electing such educational assistance or, if the member is discharged or released from active duty prior to such reduction, the collection of specified amounts from the member or an equivalent reduction in retired or retainer pay.
States that members who are enrolled in the post-Vietnam era veterans' educational assistance program shall be disenrolled from that program upon electing the educational assistance described in this Act.
Requires the Secretary concerned, in conjunction with the Secretary of Defense, to provide notice of the opportunity created by this Act to elect educational assistance under the Montgomery GI Bill.