This app dumps the NAND to USB and SD. Before you can use USB 2.0 you have to install the "modded" version of the USB 2.0 cIOS (cIOS rev7 + USB 2.0), don't worry it, won't overwrite anything, it installs as IOS222.
Nicksasa has released a NAND Flash Toolkit for the Nintendo Wii. Using this kit you can dump your Nintendo Wii's NAND to either a SD card or a USB device and then extract the contents of your NAND with the included Windows utility.
The process is a bit more involved then that as outlined in the quote below. The Wii's NAND is the internal flash that stores all of the System...