Hey I would like to install Ubuntu on a Nintendo Wii. I am using letterbomb to jailbreak and install the homebrew channel. How would I boot Ubuntu afterwards?
In short you need to install Ubuntu on the SDHC card using the live CD.
Here is a how to from 2012 where someone used Drapper Drake, Hardy, Feisty and Gutsy (last 3 are stated in the comments). He also claims newer versions of Ubuntu are too much for the WII (RAM seems to be the problem) but in the comments also states downloads for Ubuntu up to Gutsy. Of course you can follow this guide and use one of the newer versions of Ubuntu adjusting the how to as it seems needed.
This how to is from 2010 and uses a patched kernel and debian (Lenny and Etch) with a custom tar ball.
Video demo with download link: http://www.youtube.com/watch?v=f7DBAZuNusE