Brakken wrote:

It seems that Nintendo is now charging almost to full price for a Nintendo Wii if you’ve installed unsigned code on the machine that resulted in a “bricked” console. This is surprising as their warranty clearly states you wont be covered if you install unauthorized software on your Wii. Bricking your console can happen easily if you install illegal copies of VC/Wiiware games or WAD’s from unreliable places like GB@Temp. However, like I warn users in all of my reviews and guides you indeed void your warranty by installing unsigned code (aka homebrew) on your Wii. I have no sympathy for the people who pirate VC/Wiiware games and I think Nintendo should charge double the cost of the Wii to replace it.

Source: http://www.tehskeen.com/forums/showthread.php?threadid=11472

http://hackmii.com/2009/04/warranty/#more-536