Multiple Outlook users on a Single PST file?

I am guessing the answer is no, but can multiple outlook users use the same PST file at the same time from a file server?

Fortunately or unfortunately the answer is no - Outlook does an exclusive lock on the PST - even if its marked as read-only.

The idea being to get some old stuff off of the Exchange server that a couple people would still need to view...

Why do you need to move it off the Exchange server? I ask only because storage is relatively cheap, and by keeping it on a properly backed-up Exchange server the data is in a much safer place...

Alternatively, if only one can have it open at a time, would different users opening it and closing it technically work if they remembered to close it when they were done.

Not quite. Outlook only releases the lock when the user closes Outlook. So unless everyone wants to close and then re-open Outlook every time they are done, that's not really going to work either.

If its just information that needs to be referenced, you may want to look at exporting the mail items to RTF or some other document format and then leave those on a file server. Or, like I mentioned before, keep it where it is. If its not already in a public folder, move it there and keep it on the Exchange server.

You are correct, the answer is no. Outlook locks the .pst file. You could export (via Outlook) it to something sharable. Access is an option, albeit not my favorite thing in the world.