Sharing Outlook Calendar??

Sally and I have seperate logins on the same PC. As a result she has her mail and I have mine. Up until recently we had been using MS Mail but I've recently installed Outlook to help with the synching with the new phone.
Is there an easy way for us to share or synch our calendars?
*Please note that "easy" does not include installing Exchange.
Is there an easy way for us to share or synch our calendars?
*Please note that "easy" does not include installing Exchange.
