Nokia N900 guide: Setting a password for x11vnc

1. Open X Terminal (or SSH into the N900 and login as user) and type x11vnc -storepasswd
2. Enter password when prompted
3. Gain root
4. As root user, edit /usr/share/applications/hildon/x11vnc.desktop
5. Replace the line that says "Exec=/usr/bin/x11vnc" with "Exec=/usr/bin/x11vnc -usepw"

Other customizations for x11vnc on the N900 can be found here.