You could also run a VNC server, which provides the same abilities (an X display that runs on a machine, that you can disconnect from and reconnect to later if you wish).
For people who just need to do that the topic says (rather than run apps somewhere they can't see like you need to), here's a simpler solution:
In Linux:
ssh -X user@host:appname
If you want a full X display server, run:
ssh -X user@host:Xnest
If using Windows, get Xming (a Windows X display server) first, and turn on X forwarding in Putty or your other SSH client.
For people who just need to do that the topic says (rather than run apps somewhere they can't see like you need to), here's a simpler solution:
In Linux:
ssh -X user@host:appname
If you want a full X display server, run:
ssh -X user@host:Xnest
If using Windows, get Xming (a Windows X display server) first, and turn on X forwarding in Putty or your other SSH client.