Each TV has a different set of inputs. You will want to get a cable that supports not only your video card outputs but also your TV inputs. The most common are listed below.
S-Video: This is the small round input (not present on all TV’s) with 4 or 7 pinholes and a larger rectangular hole. Although not as common as the composite inputs, this would be the ideal because it is easiest. If you have an S-Video output on your video card all you need is an S-Video to S-Video cord and you should be set. (You will still need to change some options to optimize your TV display properties.)
Composite: These are the most common inputs found on television sets, consisting of 3 round single hole connections: a yellow for video and a white/red for audio.
Antenna: This is a single hole input that has a screw casing. It is normally intended for antenna or cable input and is not directly capable of receiving a video-in signal. However, an RF-Modulator can be purchased which converts the video-in signals into an antenna signal for use with your TV. RF-Modulators are available in both Mono and Stereo so you will probably want to purchase a Stereo-enabled model. This is an inexpensive way to make your TV suitable for PC video-in. (Certainly less expensive than buying a new television.) CAUTION: This is a way to make your TV display video-in compatible but the TV might not be suited to display it.