HEY - Email at its best, new from Basecamp.
MailChimp - MailChimp is the best way to design, send, and share email newsletters.
InstAddr - Disposable email address application.
Brevo - Innovative online Email Marketing solution to manage your contacts, create & send your newsletters and track your results. More than 80 000 clients. Best prices and attractive features.
Horde - Horde Groupware is a free, enterprise ready, browser based collaboration suite.
Campaign Monitor - Email marketing software built for designers and their clients to run successful email campaigns.