Auto Responders

Auto Responders automatically send people a times series of newsletters starting the day they sign up. Once you set up a series of auto responders, it goes into autopilot.

Resources

Automated Sales Helper
http://www.rapidreply.net

Personally, I've started using SendStudio. It's not the cheapest, but it is easy to install and easy to use. If there's a feature it doesn't have, I can't think of it.

See review in www.autoresponder-reviews.com