I heard about the Wii online service shutting down this month, so I thought I should pass by and see how everyone is doing before I miss my last opportunity to talk to you all.
It's only WiiConnect24 and a few channels such as the Forecast Channel. So you won't be able to send messages to other consoles or anymore, or exchange certain data via WiiConnect24 (such as Metroid Prime 3 vouchers).
Otherwise, online games will still work.
http://www.youtube.com/watchmeplaynintendo (Actual game captures - no emulators)