I actually ended up using x11vnc to do it. Here's how:
First of all, disable Desktop Sharing with Vino under System -> Preferences -> Remote Desktop.
Use synaptic to install x11vnc.
Once x11vnc is installed, you will need to create a password file that x11vnc will use. Do this:
Now, we need to configure GDM to run x11vnc when it loads:
sudo x11vnc -storepassword yourpasswordhere /etc/x11vnc.pass
Add this line to the file:
sudo nano -w /etc/X11/gdm/Init/Default
Now, we need to make a change to another file:
/usr/bin/x11vnc -rfbauth /etc/x11vnc.pass -o /tmp/x11vnc.log -forever -bg -rfbport 5900
In the [Debug] section, find the line:
sudo nano -w /etc/X11/gdm/gdm.conf
And change it to
Restart gdm (you can just reboot), and you are good to go.