I got some problems with my old nvidia card (fx5200) under ubuntu 10.10 because tv-out was always black and white (I already use the legacy nvidia driver because noveau always flickers every 12s). What is more the control panel crashes on all tv options, thus I can't configure it properly through the gui.
Here is what I added to /etc/X11/xorg.conf. Add this to the section "device"
Here are some options for the settings program to apply at session time.
nvidia-settings -a tvbrightness[tv-0]=100 nvidia-settings -a tvcontrast[tv-0]=50 nvidia-settings -a tvhue[tv-0]=35 nvidia-settings -a tvsaturation[tv-0]=160 nvidia-settings -a tvoverscan[tv-0]=10