You've just installed Debian, but your wife wants her monitor back. That's OK, you were planning on running it headless, anyway. But, wouldn't it be nice to check out some of those groovy GUI apps? Don't fret, VNC will let you interact with a desktop environment from just about any platform available.
Install vncserver (as root):
apt-get install vncserver
Choose your desired window size and color depth, then, as an ordinary user, open a terminal and type:
vncserver -geometry 1024x768 -depth 24
This will prompt you to create a password:
You will require a password to access your desktops.
The server will start and tell you where to access it:
New 'X' desktop is foobar:1
Starting applications specified in /etc/X11/Xsession
Log file is /home/jorey/.vnc/foobar:1.log
Open the VNC viewer on your remote machine, enter the hostname:screen and password (use a hostname or IP that your client machine understands), and your Linux desktop will open in a window! Network speed and processor power will affect performance, but it's amazing how many apps will run fine under VNC. You might not be able to play Frozen Bubble, but you can use productivity applications without any trouble.
To kill the server enter a command similar to this, using the appropriate settings:
vncserver -kill :1
TightVNC - TightVNC offers VNC clients for multiple platforms, including Microsoft Windows.