Is there a plugin like …

I wan’t to send mailing to users. I have database with 600K emails. I can of course create some RoR app to manage mailings and do not send more then X emails per hour, or I can learn how to do it in PHP but maybe there already is plugin like this ? It should be very simple create two tables in DB, get 1000 emails per hour from one, move to another and send template.html …