vid card with s-vid out (or composite, s-vid preffered)
rf mod that accepts s-vid (or composite, match your card) and audio.
cables to connect them (usually just an s-vid cable and whatever audio cable is required).
and of course the coax.
if your tv supports it, go HDMI. you will need a vid card with HDMI w/sound (either built into card, or header for input), and an HDMI cable the appropriate length. you will get MUCH better video quality this way.
OR... if your tv has DB15 or dvi input, you can go that route. just need the approriate card (video), and a cabling to go from pc to tv..