Hello (again)!
This isn't really a request for help, but I wasn't sure where else to post it...
It does say very specifically in your FAQ that a cron-event scheduler is required in order to get messages sent to the subscribers list on a weekly basis.
=> http://subscribe2.wordpress.com/2006/12/08/future-posts-daily-digests-dont-work/
However (and please forgive me for being a little cheeky for suggesting it) I think this could be more abvious in the description you've listed on the WP.org Plugins listing...
Do you think you could make it happen, please? :)