How to Connect My Nintendo DS to WiFi
- 1). Turn on your DS and navigate to the WiFi connection settings menu. On a DSi, click the wrench icon, navigate to the third page of options and select "Internet." On an original DS or DS Lite, select "Edit WiFi Settings" from the in-game menu. The game must be WiFi compatible to access the WiFi settings menu.
- 2). Select "Connection Settings."
- 3). Choose an open connection slot, which will be indicated by the word "None" next to the connection number.
- 4). Select "Search for an Access Point."
- 5). Select your wireless network from the list displayed. Enter the wireless encryption code for your network with the onscreen keyboard.
- 6). Select "OK" when prompted to save your settings and establish a connection with the network.
Source...