Ssh

server: install xauth
server: enable in /etc/ssh/sshd_config
server: make sure you have an X environment installed (install of any X app will pull it in)
client: set default-on in /etc/ssh/ssh_config (in place of ssh -Y)
client: make sure you have an X server environment - on windows, use x2go
if you need to become root after you have ssh'ed (for example to run wireshark), do this magic to patch in x authorization, oh yeah!

sudo su -
[root ~]# touch .Xauthority
[root ~]# xauth add $(xauth -f ~ec2-user/.Xauthority list|tail -1)