We have a Small Business Server (SBS) Windows 2003, and we need to setup a shared outlook calendar using exchange (comes with the SBS), however my client does not want to use exchange mail. In other words, they would like to use Outlook to send an receive emails using some hosted web mail service (using POP) but have the Outlook calendar shared among users using exchange on local SBS server. All users have domain accounts configured. Is this possible to do?
You mention that the client does not want Exchange email accounts. Unfortunately modern Outlook does not have a seperate client just for Calendar entries. It used to be known as Schedule+, but was discontinued and incorporated into the office Oulook.
So to setup Calendar access via outlook, your client would still need an exchange site. Not a problem from the backend using SBS. What you won't need to setup is an SMTP connector for external send/rec.
On the user side Outlook is easy to setup to start with a view of just the calendar folder. Depending on the version of Outlook this can be done either in the profile or with a switch. You can further restrict Outlook to also not show the other folders, but in reality, althoough Outlook will only be used for internal employee calendar use, they will still need contacts (appointment invitees), deleted items, sent items...
It's possible but messy, in that you have to create multiple accounts and the Exchange account will include the default folders along with the calendar.