It's proof-of-concept no more! The bubbling Wii Linux project from Albert "isobel" Herranz is now realized in Whiite-Linux v0.1a. The Whiite-Linux system enables the console for use as a PowerPC based Linux system. The initial release also allows the system to handle most USB devices, like keyboards and mice. These are the download archives, as described by the readme:

The package debian-etch-4.0+whiite-0.1.tar.bz2 contains a tarball of a standard "barebones" debootstrapped Debian 4.0 (etch) root filesystem targetted for PowerPC systems. In addition, the package whiite-linux-0.1a.tar.bz2 contains a Linux kernel build designed to run on a Nintendo Wii console.

Combined, these two packages form the base of the whiite-linux system.