I was curious myself back then as to how would my desktop look on my 29" tv ,my graphics card had this s-video out jack as well.You get these cords with your dvd player (red/yellow/white jacks) ,the cords have male connectors on both the ends while the s-video cord that you get with the card has a female connector at one end,all i did was connect one end of that dvd player cord to the female connector of the s -video cord and the other end of the dvd player cord to the usual jacks on the tv ,i disconnected the monitor turned on the tv the graphics card software detected my tv as a second monitor.
Tried some videos etc everything was working properly ,the fonts looked quite bad though unreadable to be precise.