"Rob" pointed out here that the then Cardinal Ratzinger had some interesting things to say about Jesus' descent into Hell in his book Introduction to Christianity. Well, I just found out today that Dr. Regis Martin wrote his doctoral dissertation on those very insights. It was just recently--as in last week--published by Ignatius Press. It is entitled The Suffering of Love: Christ's Descent Into the Hell of Human Hopelessness. It promises to be an amazing read.
Check it out!