Ratings and Reviews : Listing
eGroupware is a lightweight groupware system that can easily be integrated into an existing email setup. (Unlike many other systems that can only be used with the bundled MTA, POP/IMAP servers or provide that functionality by themselves.)
The core components webmail and calendar can mostly be handled intuitive by non-technical people.
It provides some advanced functionality like calendar sharing and synchronization via SyncML, the latter being not completely stable yet, however.
Allthough some interfaces are offered to connect a desktop client (SyncML, XML-RPC, ...) I had no success with that, also lacking a stable PIM client other than Outlook.
The project's website is rather chaotic, with partly outdated information scattered across wiki pages but support requests in the forums are answered quickly.