Nintendo WiFi Connection Name edit?

[Minority]

Someone educate me, how do you change your username which other people see? I had a go on multiplayer mario kart over wifi for the first time the other day and I could see other peoples names but I had no idea what they saw as my name - is it the nickname stored in the DS?

Also, how do I get my name to give to friends so they can add me to their friends list.

Thanks

 

[FeFiDoh]

also whats with the pics above name? how do u change it? just down to the emblems