Friend Code Database
From WikiTemp, the GBAtemp wiki
The friend code database allows you to share your friend codes for various games. It can be accessed with this link, or by clicking the "Wifi Codes" button which can be seen under each post.
Adding Codes
You can add new friend codes to your list by clicking "Update friend codes" or by following this link. You can then select the game and enter your friend code. Note that the friend code must have the correct format, or it won't work.
If you can't find the game in the list, you can ask a Moderator/Admin to add it for you.