DeskNow by >Ventia Pty Limited, Australia integrates in a single, easy to administer product:
fully featured mail server
advanced antispam technologies, antivirus integration and content filtering
dynamic webmail interface
digital email encryption and signing
advanced calendaring with meeting planning, free/busy search, shared calendars, task lists, resource booking, iCal publishing (Mozilla Sunbird, Apple iCal)
Outlook connector to integrate personal and group calendars, tasks, contacts
SyncML synchronization with Palm, PocketPC, BlackBerry and most mobile phones
secure Jabber instant messaging with integrated web client
automatic authentication and account import with Active Directory and LDAP servers
... and much more!... More Info »
All this at an extremely competitive price.
DeskNow can be installed in minutes, on Windows, Linux, FreeBSD, Solaris, Mac OS X, etc.