Email marketing is a key component to business today. There are so many factors involved with creating a comprehensive, well designed and received email marketing plan.  I personally setup my clients with Mailchimp because after a little training and customized design email templates, they can manage their own campaigns or work with me on new ones.  Read this well rounded post by Brandon @ Mailchimp to learn more about email marketing.  Brandon is a writer on MailChimp's marketing team.