Internet Channel
For the past two channels to work, you'll need an internet connection. Should you choose to take things one step further and actually surf the web with Wii, a downloadable Opera browser is available.
Wii Shop Channel
This is where you'll buy games for the Virtual Console - roughly $5 for NES, $8 for SNES and $10 for Nintendo 64 games. Not too high a price, though the length of some NES games makes them a total rip-off for five bucks. Purchases will be handled with Wii Points, which can be bought online or in retail stores.
Wii Message Board
An online community of sorts that'll let you leave messages on other people's Wii systems, in addition to photos and cell phone text messages. Incoming messages will also include game-related news blips, like "hey there's a new level for download" or something like that.
So there you have it. They're all basic functions, but complete firsts for a Nintendo console. Judging from the interface, however, it doesn't look all that simpler than Xbox Live. Perhaps that's where the news and weather functions come in? Maybe parents will actually get sucked into the console and decide to start playing games again. Then again, maybe not - we'll have a pretty good idea by the end of the year.