[Nottingham] email and calendaring products

[Martin Garton]

Hi all,

I'm looking for some advice on email and calendaring server software.

I need something that can be accessed by outlook and from at least one
graphical Linux based client (preferably evolution) for both mail and
calendars.

If it was only for email, I would just install one of the many products
with IMAP support. My problem is that I don't know anything about how
calendars work. In fact I suspect no standard protocol even exists for 
this(?)

Does anyone have any suggestions?

Regards,
Martin.