first of all, is this private at home? if so, privacy is not a great big thing to worry aobut.
here is how you will make a share on each of the computers so that the toher two has access.
ok, i will call the computers win2k1, win2k2, and winxp.
ok ,first of all, this is the same forall the computers, so i will tell you once.
we will use win2k1 in the example.
on win2k1 create a folder to act as the share. place this wherever you want, i prefer right on C:, but thats jsut me, you can have it in My Documents or wherever, this does not mater.
once you have it created, you are going to right click it, and select propeties from the drop down box. once the properties sheet is open slecet the shareing tab.
in the sharing options, click the radial button that says 'Share This Folder' once activated, type in a proper name for the share and click ok. Now it is open for anyone to grab on the network.
ok, now on wink2k2 and winxp, right click My Computer' and select 'map network drive' from the drop down menu.
in this screen, you will see a few things. hre are the stepst o conect to that share on win2k1:
1: select a drive leter. prefferably one above f:
2: type in the name of the share (if you know if) it would go like this \\name of the win2k1\share name
once this is done, make sure you click the 'recooncet on logon' button, so that the shareis always there.
then click ok, and.....
your done
so repeat this for the other computers and you are set.
Ches

Have a great day