need special Yahoo auto responder

I need something that can auto respond to everyone that replies to my yahoo Email(or gmail and hotmail for that matter) For example. I place an ad for a product, say 50 people respond. I want to be able to log into my account at a time of my choosing, and send all 50 people that responded to me a pre written sales letter all at one time, at the time I log in an start the process( not like an auto responder that sends out an autoresponse right away). Right now I am doing this by cut and paste and it is taking up a lot of time...if I could automat this i would save all sorts of time. Any help?

They have auto programs that can automate posting to craigslist, surely someone has a way to automate sending Emails from an Email account? Anyone?

You paddle.. Im in the same boat = (