It's a Wonderful Afterlife?

Eighty per cent of Americans say they believe in heaven. But when they're asked to describe it, many are at a loss for words. Do they think that there's another universe in the sky or do they believe that heaven is something more abstract and metaphorical? We'll explore our enduring fascination with the afterlife by talking to Lisa Miller, the author of "Heaven." Also, Carlos Eire on a very brief history of eternity.