For Mac OS X 10.2 download here.
For Mac OS X 10.3 download here.
For Linux users download here.
1. Make a directory (e.g. mkdir 12a).
2. Execute the command: fs sa 12a partnersLogin read
That will let your partner read the files in that directory. If you are also letting your partner modify the files in that directory, then replace the "read" in the command with "write".