I've just been discussing the practical aspects of implementation of the National Credit Act with a debt collection agency. Some aspects still need to be cleared up, but there has been some progress.
Additional regulations were published on 30th November 2006 which deals with much of the administrative issues. The relevant Government Gazette can be found here.
I've done a quick skim - it does clear up quite a few issues in respect of blacklisting. When I get a chance, I'll post a summary of the implications.