Sharing Folders and Files

I have set up a home network using a adsl router/modem and two machines each
with a pc card. All machines have WINXP installed. The system is fully
functional, all machines can 'talk' to each other, access the internet and
print to the printer. I want to be able to share all folders and files
between the three machines. Do I have to set up sharing for each drive,
folder and file on each machine or is their a global 'command' for each
machine to allow sharing of all files? I am beginning to think I have to go
through each machine and individually select each drive, folder and file to
share :-(.