As C.S. Lewis said (or had George MacDonald say) in The Great Divorce, "there is no soul in Hell to whom he did not preach."
In the News/Activism forum, on a thread titled The Jesus War (New Yorker Piece on Mel Gibson, "The Passion"), The Iguana wrote:
"Good point."
"Of course, that leaves the question of virtuous folk pre or post-Christ who have never had the chance to hear the Good News..."
It's not enough just to be good. You have to enter into the Covenant, and be born again, of the water and of the spirit (John 3:5). Since the requirement extends to all, it would seem only just that the Lord would provide a way for all to enter into that covenant. He has.
Peter wrote that even the rebellious who perished in the flood of Noah heard the Good News during the time between the Savior's death and resurrection: "For Christ also hath once suffered for sins, the just for the unjust, that he might bring us to God, being put to death in the flesh, but quickened by the Spirit: By which also he went and preached unto the spirits in prison..." (I Peter 3: 18-21)
However, even when a person in the Spirit World accepts the Gospel, he must still be baptized, and baptism must be performed in the flesh, by immersion in water. Paul explained how the Lord solves this dilemma by providing for proxy baptism of the living for the dead: "Else what shall they do which are baptized for the dead, if the dead rise not at all? why are they then baptized for the dead?" (I Corinthians 15:20)
The Church of Jesus Christ of Latter-Day Saints claims authority from God, through the prophet Elijah (Malachi 4:5-6), to perform this service, and it has undertaken the enormous effort to do it for all, one by one, in its temples. Of course, the ordinance is only effective if the dead person freely accepts it.
For a more detailed account of Christ's ministry to the dead, see
http://scriptures.lds.org/dc/138 Tracy Hall
Provo Canyon, Utah