Evolution for Win 32
Evolution is an incredibly versatile email/calendar/PIM that took the Linux world by storm a few years ago.
It has been called an 'Outlook replacement' by every tech site from ZDNet to InfoWorld. Evolution played a major role in allowing the Linux desktop to move into the enterprise by being able to connect to Microsoft Exchange Server and schedule/accept Microsoft Outlook Meetings.
The tremendous amount of work that it took to port Evolution and its dependencies to Windows was done by Tor Lillqvist.
OpenOffice.org (or OpenOfficeProfessional) + Evolution for Win32 = Full, Free, Open Source Office Suite!
Evolution.Win32 Website | Evolution Features | (Installer) Downloads @ SourceForge