SSH should be able to do what you are looking for, assuming you are using Xwindows as your graphical display environment on both ends.
Assuming the following:
systemA - the computer that has the application you want to run across the network
systemB - the computer you are "local" to, where you are connecting to systemA from.
Install the OpenSSH packages on both systemA and systemB (can be had from
www.sunfreeware.com).
Make sure the /usr/local/etc/sshd_config file on systemA has the following line in it:
"
X11Forwarding yes
X11DisplayOffset 10
X11UseLocalhost yes
"
and be sure to restart sshd on systemA.
Make sure /usr/local/etc/ssh_config on systemB has the following:
"
Host *
ForwardX11 yes
"
Then ssh from systemB to systemA and run the following command:
echo $DISPLAY
You should see the following returned:
localhost:10.0
This means that a X11 session is forwarding through your ssh session, so you should be able to run an X11 application on systemA and have it display on your local systemB.