I was trying to get X11 forwarding to work on Mac OS X 10.2.6 / Apple X11. This lets you run any X11 app on your Mac from any other unix system. While I could use remote X11 apps from my Mac, I couldn't use apps on my Mac from my linux box at work. Then I found a writeup on the macwrite.com web site that explains how to fix this:
Ten More Mac OS X Loose Ends Part Two - X11 Forwarding
After going through this fix (the instructions are easy to follow), just make sure you have X11.app running on your mac. Then, from any remote OSX/unix/linux box, just type:
ssh yourname@yourhost.comand you will be able to run any X11 program remotely. As a side benefit, you can launch X11 apps from the OS X terminal. Before applying this fix, you could only launch X11 apps from an xterm session.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20030911125952177