help with smartlist

hello... I have some questions about the smartlist... 1. what's a digest list? what is the digest? 2. If I make a moderated list, then I have to forward again every mail to the list, but as the FROM: appears my e-mail and not the sender's. Is there anyway to make the list to browdcast an approved e-mail but appears as send from the original sender? thanks in advanced alexander boukouris