Instructions
Select the "Wii" button on the bottom left corner of the main menu.
Select the "Wii Settings" button.
Press the arrow button to scroll over one page, then select the "Parental Controls" option.
Enter a 4-digit pin number, confirm it by entering it again, then answer a security question as prompted.
Select "Other Settings." You will be provided with a screen that explains which settings you can change.
Hit the "next" button until you see "Use of the Internet Channel." Select "Restrict" and then "Confirm." Now a 4-digit pin code will be required any time someone tries to access the Internet.