Remote desktop, or using a remote session, is a very important part of advanced computing. The ability to do this securely is important as well.
Using ssh, Xephyr and a light weight desktop manager, an encrypted, secure, fairly fast remote desktop setup is fairly easy to implement.
First, you'll need to install SSH on the remote machine:
$ sudo apt-get install openssh-server
To make your SSH installation more secure, you should use the public key authentication method of authentication.
Then you'll need to configure SSH to forward X. Make sure the x11Forwarding is set to yes (it is by default) in /etc/ssh/sshd_config.
Next, install a light weight window manager on the remote machine. I used xfce (sudo apt-get install xfce4), but you can also use blackbox or several others.
On the local machine, you'll need to install Xephyr, which creates a new X server inside your existing, running X session.
Then, use these instructions to start Xephyr and start an SSH session that forwards the X session to the embedded X session.