Forwarding X over SSH in 3 simple steps

1. sudo vim /etc/ssh/sshd_config and make sure X11Forwarding is set to yes on the box you are ssh’ing too.
2. ssh -v -X -C xxx.xxx.xxx.xxx  (-X specifies X forwarding, -C specifies compression, -v is verbose).
3. Once logged in, simply execute xinit if it’s not already running on that box, and then fire off the name of your application.  Examples:
   1. gnome-session (will start GNOME)
   2. startkde (will start KDE)
   3. firefox (will forward Firefox to your machine)

Via TuxTraining.