Right click on your My Computer icon. Click Properties. Click the Computer Name tab. Click the Change button. See where it says Workgroup? Make sure that both XP computers have the same workgroup name. You can leave it if they both say "Workgroup" if not name them both to Boz if you want. If you change them you'll have to reboot them.
All nice and worgroupy? Sweet! Now right click on the folder you want to share. Click Properties. Click the Sharing tab. Click the "If you understand the security risks but want to share blah blah blah." line. Click the "Just enable file sharing" and shut the fuck up radio button. Click OK. Check the "Share this folder on the network", fill in the box with a share name (whatever you want, something simple). You can click the "allow everyone to do stuff to this folder" check box if you want, but if your just copying from it, its not necessary. Click OK. Now you go to the computer you want to copy the files to and double click My Network Places. Click View Workgroup Computers it's on the left hand sidebar menu. You should see the computer with the shared folder in there, double click that and your share should be there.
Hope I didn't leave anything out. Good luck!