Our outgoing or SMTP mail server setting is : mail.yourdomain.com
(where yourdomain.com is your actual domain name)
NOTE : Remember to enable "Outgoing Mail Server Authentication" in your e-mail program. With out enabling this setting you will not be able to send e-mail from our servers.
In outlook Express you can enable this under (Tools > Accounts > Your mail account > properties > Servers > Outgoing Mail Server > (enable) My server required authentication).