Here is my Mii Code 2793-1204-4866.
I've also finally worked out where the other code is! I knew what it was just not where to find it

It's the console code, if you swap console codes then you shouldn't need to swap the code for individual games. It also means that you'll be able to send messages to each others console using the Wii message board.
You can find your code in the address book found after selecting to create message in the wii message board. Mine is 5783 3858 1013 2947.
Mario Kart is the only thing i'm currently interested in playing online on Wii
