Advanced SMTP Server is a system-tray local SMTP server program for Windows that lets you send email messages directly from your computer to recipient mailboxes. Along with a mass mailer the program can be used as a relay server for sending newslette

A Mail Server for Windows XP/2003 with POP3 (Server and Retriever from Providers), SMTP Server, IMAP server, HTTP (webMail) Servers included, and an AntiSpam mechanism.

The Axigen Free Mail Server is a great alternative to open source: it is an all-in-one, turnkey messaging solution, with an amazing number of free users (100 basic email users, calendaring for 5 users included).

MailEnable Enterprise Edition is designed for organisations or ISP`s dealing with high volumes of mail, requiring greater control and flexibility over mail services.

Mail Direct is a program designed to send emails fastly, safely and directly to recipients, bypassing your ISP`s mail server. It`s not a mail client but it has a built-in SMTP server which can be quickly setup for use with your favorite mail client.