Find out the IP number (or name) of your Mac. There is
a menu command in BetterTelnet that will show your IP number. Then in your
telnet or ssh connection to the unix host, type:
setenv DISPLAY 192.168.0.1:0
Obviously you will have to replace the 192.168.0.1 in the above example
with your IP number. Note that this command is CASE SENSITIVE, and don't
forget the trailing 0. If you are on a dialup connection, you can use the
domain name for your dialup connection, eg:
setenv DISPLAY myhost.dyndns.org:0