How can I set up calendars on a Mac so that I can see calendars for other teammates (and vice versa)? We don't have a mail server but do use MS Office (Entourage as mail client) and were thinking of using Apple Mail.
You will need some kind of network service. This can be a groupware solution (Exchange, Zimbra, Kerio), a dedicated iCal server like Davical or even a hosted calendaring service like Google Calendar.
Entourage will likely not work with most solutions though, but iCal will.
Edit: One easy and cheap solution might be to put some old machine with a Lion+Lion Server install somewhere and use it's builtin iCal Server.