http://wii.marcansoft.com/parental.wsgi

If your parents (or you) have set up a parental code on your console (works on either Wii or DS, DSi) and forgot it or parents wont tell you, go to the link and enter in the confirmation code that the system will give you when you keep clicking the "I forgot" button when accessing parental controls.

Tested this, worked on both my DSi and Wii. (I forgot the code I had set the systems up with.)