This is my favorite Wii emulator. It plays pretty much every Wii game, requires basically no set up and doesn’t require a powerful computer to play.
Its available for Windows, Mac and Linux.
To get it just go to their download page:
Get the most recent stable version unless you know what you are doing and are prepared to deal with any problems. I use the stable version because I just want it to work.
To install it just run the installer (or click the app on a MAC) follow the instructions and thats it. Ou are up and running and ready to play your wii games.
One thing that you can do to make it nicer to use is give it your game directory so that it can load your games without having to navigate to it each time.
Just double click in the main window and you will see a explorer window where you can set your games directory. Dolphin will do the rest and scan your library.
The last thing you will need to do is to set up your light gun.
This is a great tutorial on getting this up and running. It is using the Aimtrak lightgun to demo this but the process should be the same for anything that inputs as a mouse.