Just checked on a couple of Windows2000 servers and workstations and you don't need to be a domain controller to restrict access by user.
What you would need to do is:
1. Create the same users and passwords on both computers
2. Change the admin password on one of them.
3. On PC-2, create the share you want.
4. Click on Permissions
5. Click on the Add button
6. Add in the local adminstrator's account on that computer (I would also recommend having one additional local admin account you can use as well)
7. Scroll down to you see the lists of names and add the ones you want with the permission level you want.
8. Remove Everyone from the list.
9. Now just don't give out the PC-1 users or passwords to the people using PC-2
What you would need to do is:
1. Create the same users and passwords on both computers
2. Change the admin password on one of them.
3. On PC-2, create the share you want.
4. Click on Permissions
5. Click on the Add button
6. Add in the local adminstrator's account on that computer (I would also recommend having one additional local admin account you can use as well)
7. Scroll down to you see the lists of names and add the ones you want with the permission level you want.
8. Remove Everyone from the list.
9. Now just don't give out the PC-1 users or passwords to the people using PC-2