Instructions
Move your DSi XL to within range of your wireless access point. The closer you are to the access point, the better your Internet connection. Most routers have a maximum range of a few dozen feet.
Turn on the DSi XL and touch "System Settings" upon startup.
Touch the right-pointing arrow two times to access the third page of "System Settings."
Touch "Internet" and select "Connection Settings."
Tap "None" to the right of "Connection 1." The wireless network you set up will save to this connection.
Select the gray "Search for an Access Point" option. The DSi XL will show a wireless network results list.
Touch the access point's name in the results list.
Enter the access point's password and tap "OK." A summary prompt appears asking to save the settings.
Tap "OK." A prompt appears informing you the settings have been saved and asks you to test the connection.
Tap "OK." The DSi XL connects to the network.