You must have a Nintendo DS, wireless router and a broadband conncetion to connect to the Nintendo WFC Network. You will be able to play the NDS game with other online users worldwide. The most easiest method is to use the "Search for an Access point" feature.

"Search for an Access Point"

Okay, great. You’ve chosen to connect using the "Search for an Access Point" feature.

At the Setup screen, tap Nintendo Wi-Fi Connection Settings:

…and then one of the Connection slots:

…and then "Search For An Access Point":

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The Nintendo DS will then display the name of your wireless access point.

My Access Point has a blue, unlocked icon:

If your Access Point has a blue, unlocked icon, tap the Access Point name, and then ‘OK.’ The Nintendo DS will then establish a connection with your router. Back out to the main screen of your game and your ready to play online. It’s that easy!

My Access Point has a red, locked icon:

If your Access Point has a red, locked icon, the Nintendo DS has detected WEP key security on your router. Tap the Access Point name on the Nintendo DS and then enter the WEP key for your router on the following screen and tap ‘OK’ to save the settings. Tap ‘OK’ again and the Nintendo DS will then establish a connection with your router. Back out to the main screen of your game and your ready to play online. It’s that easy! It does not support router with WPA key security.

My Access Point has a gray, locked icon:

If your Access Point has a gray, locked icon, the Nintendo DS has determined your router’s security settings are not supported by the Nintendo DS. In order to connect to the Nintendo Wi-Fi Connection, you will need to either switch to WEP security, or remove the security setting of your router when connecting with the Nintendo DS.
For information on how to access the security settings for your router, click here.

My Access Point isn’t being displayed:

If the Nintendo DS is not displaying your Access Point, click here for tips on what you can do.