Groupware server Is that what I want

Hi, I'm a single computer consultant with three different offices scattered here and there--two have broadband, one dialup. I am now using Outlook at one location for my email and calendar and contact info. I use Outlook Express at the other two locations. I have a HP Jornada PDA that I carry around with calendar and contact info--this syncs with the outlook database. I try to remember the email I receive on each of the machines (I don't receive that much email).

As you might imagine, this is less than optimum. I was wondering if there was some sort of Linux based software package that would act as a server for email-calendar-contact info and that this info could be downloaded into a client (maybe Outlook) at my three locations. I would like to download the info because I may need to refer to email-calendar-contacts while offline.

Is this what 'Groupware' is? If I were to use a groupware server like OpenExchange or Kolab, could I download my email-calendar-contacts into my local systems so I could view it offline--or would I have to access the groupware server via a browser interface of something like that?

I am not sure exactly what software category my server need would fall into, and also if something like that exists.

Would some kind person who knows something about this give me a pointer or two?

Thank, Greg Laird