There's an option in your Wii settings for 480i or 480p. Make sure you're using p. Other than that, there's not much you can do. LCD screens are fixed resolution. It has to scale anything that doesn't fit its resolution. Unfortunately, some TVs' scalers are better than others. You might be able to run it through a TV card to a PC and then out to the TV through a VGA connector but I think the lag would kill you there.