A quick warning, there are increasing reports across the internet that the latest system update (4.2) for the Wii is causing problems, including completely locking it up.

The update doesn't appear to add anything, it mostly seems designed to stop people in the home-brew community from running their own software on the Wii.

So all in all, it might be best to avoid doing an update for a few weeks until we know that it's alright.