EaseCentral - EaseCentral takes the headaches out of administration so you can focus on benefits.
Mailman - Mailman is free software for managing electronic mail discussion and e-newsletter lists.
PlanSource - PlanSource is a web-based human resources and benefits administration solution servicing small and medium-sized businesses.
Mailman 3 - Dedicated Mailman 3 installation. Unlimited lists/configuration. Free subdomain at mailman3.com. Dedicated support for list admins.
PeopleKeep - PeopleKeep has created a new way to offer benefits called personalized benefits.
MailChimp - MailChimp is the best way to design, send, and share email newsletters.