Instructions
Turn your Wii console on. Use the "A" button on the Wii remote to select "Wii" in the bottom left corner of the screen.
Move the cursor to "Data management," and use the "A" button on the Wii remote to access the Data Management Screen.
Move the cursor over "Wii Channels," and use the "A" button on the remote to enter the Wii Channels screen.
Select the Wii channel you wish to delete with the Wii remote.
Choose "Erase" from the list of options that pops up to delete the channel.