Launch Gedit while sshing in terminal
Firstly make sure X11 is installed (it's an optional install on the OS X dvd)

You need to ssh in with X11 forwarding.

Open terminal and type ssh -X username@host  where username and host are the relevant details.

This will log you in.  Once logged in type gedit and the X11 server on your mac will start and show the gEdit window.