We've got some good news and some bad news. Let's start with the bad news: Nintendo's latest Wii menu update (3.3) effectively plugs up the Twilight Princess hole that served to foster a homebrew community – or, perhaps more accurately, it casts the homebrew community into a realm of darkness. According to the update, "Beacuse unauthorized modifications to save files may impair game play or the Wii Console, updating to Wii Menu version 3.3 will also check for and automatically remove such save files."
As for the good news, the Wii menu update also lets you move a Mii from from the Mii Plaza to the Mii Parade, and really, isn't that awesome enough to make up for killing homebrew? The countdown has begun for someone to produce a Wii downgrader.
Update: According to various sources, the Homebrew Channel still work if it was installed before the menu update.