Wii # is different from Friend Codes.
Wii # is the long number you find in the Wii message board, you give that out to other people that you want to add as Wii friends, and then you take their code and add it. This way you can send messages, and you will know that it works if you can send messages.
As for Friend Codes, thats the code that comes with a game. You need to get someones Game code to play online with them, and they need yours to register yours as well, especially for games like Brawl.
So you need to PM users for their Wii numbers if you want to add them to Wii, here is the thread for those numbers (last pages contains post from new members to the forum so adding them is your best bet) just be sure to PM them telling them you added them to your Wii and give them your code as well to add you back:
http://www.wiichat.com/nintendo-wii-...e-page616.html
And if you want Friend Codes for Brawl they can be found here, do the same with the Wii numbers regarding PMing members for best results:
http://www.wiichat.com/super-smash-b...end-codes.html