Where to find Wii game ID?

If you don't have the right game ID the games won't work. Can anyone tell me how you are supposed to know the game ID? I see the middle 4 of the serial# but then what? For example Mario kart is RMCE01...Kirby's dreamland is SUKE01. But then Rayman is SOJE41 and Naruto is RNXEDA So how do you know the last 2 numbers/letters?