For follow-up discussion and general commentary on the topic. Comments are sorted chronologically.
I believe that we need to keep cultural differences in mind. Back then, women had a much different role in society than they do today. Paul may have commanded the women to remain silent in those cases in order to keep the harmony and peace as men had a more authoritative role than they do today. Paul may have written something different today as it has become very acceptable for women to have a more active role in the church. For example, would he command women to cover their heads today? And no, I don't believe that the hair is a "covering" as some may suggest.