Setting up a TV to view what is on the computer is fairly simple or easy to do as long as the necessary cables are available. Currently there are a few ways to hook up a TV to a computer with S-video, HDMI, or DVI. S-video is the older of these and is round it does not carry audio so a cable will have to be bought to go from the sound card to the TV.
DVI is next and can carry high definition signal to the TV. It as with S-video, does not carry sound though and will need a additional cable to carry the audio to the TV. HDMI is the best as of right now because it carries not only high definition but it also caries sound, which is great for a quick and clean setup. Of course all of this will depend on which kind of TV you have. Most TV's currently do come with S-Video, HDMI and DVI connections. S-Video is slowly being phased out and will soon disappear.
The best thing to do is know what type of TV connections and computer connections you have so that you can buy the necessary cables. Then once you find out which cables you need s-Video, HDMI, or DVI then you can go to your local electronics store and buy what you need. Although I find it much cheaper if not easier to buy the items online. S-Video, HDMI and DVI cables are often expensive at a local store buying online can save you some money. Of course use your favorite search engine or trusted online store to buy what you will need.