For more than a year, some economists have predicted the bursting of what they call the housing "bubble." When we first aired this program on May 9--things haven't improved in the meantime, Fortune magazine said the boom was already over. Since then, sales of new homes have fallen and the inventory of unsold homes is at a record high. If prices drop, what's the fate of mortgage-holders with interest-only loans who think their houses are banks? What are the consequences for the economy as a whole?