I've had a Wii for almost half a year, but haven't had any games that would benefit from posting Wii/Mii friend codes. That is until now.
Since this knowledge may allow me to play Mario Kart with friends over the net, here are the relevant codes:
Wii: 8358 4043 2718 9262
Mario Kart: 2492-8471-9003
Comment here with yours if you wish to play.
I know Samba de Amigo also has a friend code. I haven't written it down... But if there's interest, tell me and I'll post it here as well.