Also make sure that you are running in mixed b/g mode, not g only mode.  You can use WEP security if your router supports it.

The Nintendo Wi-Fi USB connector is no longer manufactured and quite franky I don't know why. They ceased production over a year before the release of hte Nintendo DSi yet still offer it as a connection option.

To the author of this post: It would be a better option to purchase a Nintendo Wi-Fi USB connector through various online retailers as WEP securityt is about as secure as an old fashioned phone jack connection nd may leave you open to an attack from a virus that previously couldn't get through WPA and its variations. They are pretty expensive but it is well worth the cost and allow you to play all DS games online that support online play. It is recommended that you purchase the one that is labled "Nintendo Wi-Fi USB connector" across the housing as it is an official Nintendo product. Others, while they claim to give the DS intrnet, may or may not allow you to connect.

I think they're slowly compensating and making DS games compatible with both WPS and WEP security, like Pokemon Black and White.

I disagree with the comment about WEP security.  While it may be less secure than WPA because it uses a fixed key, a hacker in your neighborhood would still need to obtain this key.  While there are various methods that may be used to obtain the key by monitoring broadcasted network traffic, no hacker is going to waste their time trying to hack into somebody's home wireless network.

A large corporation that has access to a number of people's personal information would be a better target and should not use WEP to protect its wireless network.

You are correct that if someone hacked into your wireless network, that person could potentially infect your computer with viruses or spyware, perhaps by using some sort of DNS spoofing technique to trick your PC into going to the wrong web page when you type the URL into your web browser.  However, a hacker could potentially do this at some other point on the Internet, putting you and many others at risk.

That being said, whenever you access banking or other sites that contain personal information (even if you don't have a wireless network), keep an eye out for suspicious changes to the website, and make sure the web browser is indicating that the site is secure before you log in.  Some banking sites put a personal message for you after you enter your user name but before you enter your password.  Make sure that the message is there and familiar to you before you enter your password.