if your taking about a desktop your easies way is to buy a vga to vga connector if you have a vga port on you tv most flats screen tv's do but if your a lil older in the tv place, your best bet is to upgrade to a pci or pci-e graphics card thats had s video output then buy an s video to composite cable to go directly form back of pc to connect to the tv
make sure your pc has pci though