.PST folder used by same user from multiple machines

[Okhuntin]

SItuation: User has three machines, 2 are on Outlook 2K, 1
Outlook 2003. Has .pst file stored on network and then
all machines are configured to point back to that central
folder. Could access .pst file from multiple machines
prior to upgrading one to 2003, since then can only
open .pst file from one machine at a time. Any ideas or
workarounds to have central personal folder store OFF of
exchange server and have it accessible by multiple PC's at
same time.

NOTE: One user using multiple machines. NOT sharing w/
other users.

Thanks in advance.
Brian