I've run my own web server for years (Fedora) with Postfix, Amasvid-New, Dovecot and Squirrelmail.
Where I work uses Lotus Notes and I was getting jealous with my Palm Pre being able to sync contacts, and calendar and well as having push email.
On top of that, the Squirrelmail interface although functional isn't exactly capable of contact and calendar syncing. Not to mention lacking in user friendliness.

As if by chance, I spotted an article in a recent Linux mag that just so happened to mention that Zarafa could do all this sync stuff looked pretty and was being shipped with Fedora.

Well I though I'd give it a go. It took me 3 days to work out how to configure/implement, then work out a way to import the existing mails from Squirrelmail/Dovecot to Zarafa.
An effort well worth it. Dovecot and Squirrelmail have served me well, its Zarafa all the way now.

Next stop was syncing to my mobile. Z-Push was the only option here, and that took all of 15 minutes to install. The Palm Pre works exceptionally well with the Z-Push. Actually better than the implementation from Lotus Notes.

Thank you Zarafa!