In your standard TV, there are 480 horizontal lines, interlaced. HD can go to 720 progressive or 1080 interlaced. S-video will help with clarity, but doesn't change the number of horizontal lines, the same with component connections, again better than SV but no increase in the horizontal lines. to do that, you'd need an HD capable TV.
BTW DVD can output 480p if it's a progressive player.