To actually backup Wii games, you first need to know what is actually required. This means you need to know what you need and what you have to do. To begin with, you might already be familiar with the games that you get are copyright protected and there is a protection from copying. This means, you can not normally copy from the disc just as you would copy other files.
To break this protection, we need specialized programs which do it for us. Such software are available online these days and most do cost you a lot. There are, however, some software which are either costly nor worthy worthless like what most of the software are. You must bear in mind that this is the important part, so getting the right kind of a software is the most important stuff.
Once you have the software, the rest of the process becomes damn easy. The software usually lets you create an image of the game disc onto your hard drive. With this, all you need to do next is use a CD / DVD burning program to burn the image file onto your new empty disc and your back up is ready! You can do this for all the games that you have gotten because once you lose a game that you bought, you can not get it back. Imagine if you have lots of such games. That is why it is often suggested that you go in for good recommended software for the image creation.