Assuming I understand what you are trying to say, it sounds like both user
accounts on Windows need access to the same PST file. This is pretty easy.
What you need to do is create a PST file in a common place like C:\DATA.
Make sure that "Everyone" has full control on the C:\DATA folder. Once that
is done, each user on Windows can create a mail profile that uses that
common PST file in C:\DATA.
Now a word of warning, Outlook opens the PST file for exclusive use. This
means that if you are big fan of Windows XP/Vista fast user switching that
you won't be able to run Outlook under both IDs at the same time. Has to be
one or the other.
Now if you really meant your looking for some idea on how to sync data
between two PST files, then take a peek at
http://www.slipstick.com/outlook/sync.asp for some ideas.
