For my first week with the Wii, I only had the supplied cable (non-component). Everything worked perfectly, but I am on a 50" plasma, so I wanted component.
I searched around and finally found a place with a component cable (I believe it's the standard nintendo one, but I'm not sure). Plugged it in, everything looked fine. Until I started actually navigating through the Wii menus. Certain screens (loading screens, Mii creation screen, Internet channel, when you die in lava in Zelda) have almost an interference look to them.. on the top half/quarter of the screen only. Now, I do have a component switch, so I'm going to try directly connecting the Wii, but I have a wierd feeling that it might not be that. Only because the interference issue only happens on certain screens (it doesn't happen when I'm actually playing a game, like walking around in Zelda, or when you type using the on-screen keyboard in the Internet program).

...nobody has any ideas?

Does it ever hapen on other games? Or is it just the Zelda game? and also, is it just you that's noticed that? Or can other people see it too?

Happens over many different screens, not just Zelda.
And everyone can see it, I en't crazy.

If I directly connect the Wii to the TV (no component switch), and it still screws up, I'll take a picture. Maybe that'll help.

Ask for a replacement cable, yours might be faulty. Mine works fine, but I did get black and white only once. A simple restart fixed that up.