The Nintendo Wii Steering Wheel Controller Accessory is packaged either by itself or you can purchase it along with Mario Kart for the Wii. However, the steering wheel accessory can be used with multiple Wii racing titles. I actually prefer to use the steering wheel over the controller alone in my Wii racing games. It adds a more realistic feel to it.
The biggest downfall for the Nintendo Wii Steering Wheel Controller Accessory is that the steering wheel does not include the controller. You have to place a Wii controller you already own into the wheel to play. It works with both the original Wii controller and the Wii Plus controller. However, if you already own any controllers this isn't that big of an issue.
The Nintendo Wii Steering Wheel Controller Accessory itself is pretty self explanatory on how you place the controller into the wheel. There is an opening for the controller and even has a spot for your wrist strap to go through so you don't have to remove it.
Overall, I recommend the Nintendo Wii Steering Wheel Controller Accessory to Wii racing fans. It adds an additional realistic steering feel, plus it makes it a little easier for younger kids to play.