Things You'll Need
Instructions
Purchase a video converter. On the Wii side, the converter will need a standard yellow RCA video jack for composite analog video signals. On the monitor side, the converter will need either an old-style VGA port, or a newer HDMI port (or a DVI port), depending on your monitor's hookups. The Wii itself does not produce high-definition video, so don't spend money on a converter with an HDMI port unless your monitor has no VGA hookup. This piece of hardware will cost you from $30 to $200 and can be purchased online or at most larger consumer electronics stores.
Plug your Wii's RCA red and white stereo audio cables directly into your computer speakers. If your speakers only have a single RCA audio jack, then you will need to use a mono-to-stereo combiner cable, which has red and white ends for your left and right stereo, and a black end with the combined signal. You can then plug the black end into your speakers.
Plug your Wii's yellow video cable into the jack on the video converter.
Connect your monitor's data cable into the appropriate port on the video converter.
Read the converter's operating instructions to see what video options you will have once you start up your system. Most converters will give you the ability to adjust the aspect ratio and the screen resolution. Some higher-end converters will also provide you with other options.
Fire up the Wii and test out a game to make sure your connections are sound. Adjust the settings as needed. Remember that the graphics will not be any better than the Wii itself is capable of producing, so, for example, don't expect HD performance simply by plugging the Wii into an HD monitor.