Dom you should check this http://www.forgehub.com/forum/videos/20697-advance-video-capture-guide.html thread out, its filled with crazy amount of answers, dont be afraid to ask if you need help on something specific.
Actually, I have heard it's possible to link an A/V type cable to a digetel camra and record whats playing on the TV, if you already have a camra this could be cheeper.
A/V is the power cord. Lulz. What you are talking about is the RCA jacks on some special cameras. I don't recommend it whatsoever.