The Old Bloke wrote:

My wife and I have Outlook 2003 and have a simple home network.

Can we share each others Contacts and Calendar?

If you don't both want Outlook open at the same time, yes. Put the PST in a
network share and add it to a mail profile on each machine. As long as
Outlook is open on one machine only, it should work, albeit unsupported.
You may find rules problematic as well.
--
Brian Tillman