Instructions
Select the "Wii" icon on the bottom of the Wii Channel Menu. Select "Wii Settings."
Select the arrow on the right side of the Wii Settings screen until you reach Wii System Settings Menu 3.
Select "Wii System Update." When prompted, select "Yes." Select "I Accept" to accept the terms of use. The Wii will check for any new system updates and automatically apply any that are found.