www.atmail.com
Features Include
Complete WebMail/Email-server ability
Supports POP3, IMAP and SQL mailbox protocols
Anti Virus Support for inbound / outbound mail
Complete Web Admin control. Includes installation , site branding, managing user accounts, security settings, mass mailing and much more.
Full source code included
mySQL Backend support
Support for wireless devices
Fully featured scheduler and Task utility
WebMail interface for mail encryption
Groupware Support
Group Address Book
Global Calendar
SMS alert for new email or messages that match a filter
Site/User-level Spam Filter with Spamassassin Support
User Mailbox Quotas
Mailbox Sorting/Searching feature
Multiple Mailboxes & Email Personalities
HTML templates for easy customization
Multi-lingual versions available
Multiple interfaces for different browsers
Import scripts to migrate data from existing email-servers
Unix and Windows Support
And more.