You can just join servers. Of course there will be clans in this game. It will work the same like PC clans ( thank god )
You create a server ( room ) with a password. Talk to youre friends about wich time and password. Let them join and you can practice.
Clanfights? Contact opposing clan, send them invite or password to youre server and youre on youre way to a clanwar.
I really cant wait. And like someone said, a lot of games have a few maps for the online version. I might even go ahead and buy a wiizapper!!!!
I totally agree with you on this that this might prove the wii is perfect for fps!