Are you serious?? It's a major new federal law which takes effect 10/28/04 that creates a new negotiable instrument, the "substitute check" which is a paper reproduction of an original. It will permit any bank in the chain to image the original, keep the original, and merely transmit the paper reproduction or, if the next party in the chain agrees, transmit an image instead of paper.
Articles that will help give you some insight are on the
BOL Check 21 page. Read from the bottom up to go from big picture to smaller details.