If you want to change the directory that 2 computers use for Remote Communication under the NewStim package, you'll need to do the following.
First, the 2 computers that you'd like to have communicate will need to have access to the same drive. The easiest way to do this is to mount the same shared drive on the 2 computers; this drive can be physically located on a server to which both computers can gain access, or it can be on the analysis computer itself. The software program DAVE from Thursby software allows OS 9 computers to mount shared drives on Windows XP machines when the XP Firewall is turned off (not sure how DAVE does with Vista or Windows 7 servers).
Then the changes are straightforward:
1) On the stimulus computer, edit the file NewStimCalibrate.m to change Remote_Comm_dir as described in the installation notes (pre-July 2010 or current).
2) On the analysis/acquisition computer, edit the file NewStimCalibrate.m to change Remote_Comm_dir as described in the installation notes (pre-July 2010 or current).
3) If you use FitzStim4, edit the Remote_Comm_dir line in SteveGUI.m on the stimulus computer to be the same as in NewStimCalibrate.m, step 1. (Is this right? Need some help here.)
[Note: there is a system for communicating with sockets that should be relatively operating system; it runs on Mac OS9, Mac OSX, and should run just fine on any unix and on PCs. However, in testing with a Mac OS 9 stim computer and a Mac OS X analysis computer, I have found that sockets were not nearly as reliable as file systems for really long-term communication, and I don't recommend using them. It's possible that the library, which is by a third party and is called tcp_udp_ip (though I have made modifications in the version distributed here), could potentially be made more reliable with more effort.]