BITFUNX NGC Component Cable Adapter - Supports Video (3RCA) and Audio (2RCA), Plug & Play Video Game Adapter with No Lag, for NGC Console (6 ft)

You didn't say what kind of inputs you have on your TV. If all you have is HDMI, you'll need a converter and upscaler. If you have component inputs, then I would get an aftermarket Gamecube component cable and run it in progressive scan mode when you boot it up. I got this Bitfunx for my 40" Samsung, and it looks great!