If your GF4 card supports VIVO (Video In, Video Out), the middle one would connect to another cable that has 1 RCA video in, 1 RCA video out, 1 S-Video Vid in, 1 S-Vid vid out .. that's what I have on my GF4TI4200.
if you plan to use TV a lot, get the card w/ Conexant chip in it (goto Tvtool website FAQ and msg board, they have list of GF4 w/ conexant chip). Conexant chip said to have much better TV output quality than philips chip (my card has philips 7108, but w/ S-video out, the quality is adequate for me, but i don't watch DVD on PC tho, so u might want to consider it)
TVTool