Let's address the second question first.
Rob said:
My main problem is that in earlier versions of office the file type was
actually labelled with a pst file extension, in Outlook 2003 there
seems to be no such file extension.
It's not Outlook that's causing your confusion, I suspect, but your version
of Windows. I think you're using Windows 2000 or XP in its default
configuration, which hides known (i.e., registered) file types. Open
Windows Explorer, click Tools>Folder Options>View and uncheck the "Hide
extensions for known file types" option. While you're there, select the
"Show hidden files and folders" option. The default location for your PST
is the (hidden) folder %UserProfile%\Local Settings\Application
Data\Microsoft\Outlook.
I have one computer with two users. I want both users to have the
same access to the same Email accounts and pst files. I have tried
allowing permissions for the second user in the first users
Application data\ username\ etc folders and it hasn't worked.
Log on as user one. Create a folder under Shared Documentsm like Shared
Documents\Outlook. Move that user's PST to that folder. Start Outlook.
WHen it complains that it can't find its folders, browse to the PST in the
shared folder, select it, and click OK. Outlook will open the PSt and be
back to normal. Close Outlook and log out.
Log in as user two. Rename that user's PST's file name (keeping the ".pst"
extension) and start Outlook. It will complain. Browse to the shared PST,
select it, and click OK. Outlook will finish opening and you'll see exactly
the same folders user one sees. You can add in user two's original PST if
you wish with FIle>Open>Outlook Data File and either use it like that or
transfer data from it to the shared PST. User one won't be able to see it,
since that user has no permission to it, but I can see value with each
account having the shared and the private PSTs.
By the way, only one user at a time will be able to use Outlook, since PSTs
are single-user files, but if each user has a separate Windows account, even
with using Fast User Switching, it shouldn't be a problem.