I have been looking and looking, but I cannot find out how to enable 2
computers to use a single Outlook express file.

We just got a new laptop (XP, Outlook 2007), and we want it to be able,
along with our old desktop (XP, Outlook 2003) to share all the data, because
they will have the same guy using both.

From what I've gathered, Outlook saves it's data to a PST file, which I
found on the server. When I tried to add the pst file as a Data File to the
new laptop, I get an error, saying that that file is already in use.

Is it even possible to have 2 computers synchronize Outlook so that going
from one computer to another, they look exactly the same? (I realize that
they have different versions of Outlook. So, is it possible with the current
setup, do they have to both be 2007, or is it just flat-out impossible?)

Where do I start?