e-mail advise please

Im not very clued up on this side of PC life, so please treat me like a novice.....
I have 6 PCs, all using Outlook for e-mail. I would like them all to share and update the same .pst file for contacts/e-mail/tasks etc, and be able to log on to any one of several e-mail accounts on any one PC.. When I point them all to the same folder/file on the one network PC, I get a file share violation message, and can only access e-mail when I shut down Outlook on the other PCs.
How can I achieve this please??

Exchange server

I'm assuming that it is outlook xp.

http://support.microsoft.com/default...b;en-us;291627

Yeah, sorry - its Outlook 2000, I only do this as XP wont let me share address book with Outlook Express, whereas 2000 will.