Thanks very much, Incognitu and Myzdoxae.
The problem with Egroupware for me and this little office is that it appears to require the implementation of an MSQL-compatible database in order to run. That's just a couple of orders-of-magnitude more that my new bosses will accept -- it's going to be a trial just getting them to consider a new web browser like Firefox.
Rainlendar is much more likely, and I'm working through the documentation to get a sense of what it would entail (if I had to administer it for four peeps).
I must confess that I'm a trifle disappointed, insasmuch as I got a Sharp Zaurus a little bit ago and
KOrganizer runs nearly perfectly in Windows.
http://korganizer.kde.org/korganizere/korge.html
It's free, super-feature-rich, platform-independent (to a degree) and allows for file-synchronization. I can't seem to get it to access .wab files though.