Instructions
Turn on your Nintendo DSi and tap the wrench icon on your screen.
Tap "Internet," followed by "Connection Settings" and "Advanced Setup."
Tap "None" beside "Connection 4."
Tap "Search for an Access Point." Wait for the Nintendo DSi to locate all nearby wireless signals.
Tap your nearby wireless signal.
Type your WPA code and tap "OK."
Tap "Save Settings," and then "Yes" to run a connection test. If the DSi says the test was successful, your Internet is properly configured. Otherwise, ensure you typed the code in correctly and followed the steps thoroughly.