Hi,
I have to run something like that. We only have two email PCs, and they both run Outlook 2000, and access the IMAP server. Each user on the machines then accesses the same messages. It's not perfect believe me, but it does the job. There are a few annoyances, pretty much all with Outlook though! For example Outlook doesn't let you put a copy of all sent messages into a different folder. However I can't find an email client that actually works, looks good and is easy enough for my boss to use! I've tried Netscape (Doesn't keep to IMAP protocol and desn't work), Eudora (Looks bad, and hard to use), Mulberry (very good but difficult to use), Pegasus (Can't talk to the e-smith's IMAP server), and goodness knows how many more little ones.
Good luck!!
Matt
PS: Have a search on the forum for IMAP, there's lots of good, helpful posts on it...