I really want to throw it out there that the Nintendo DS Wi-Fi USB Connector is a piece of shit. It's ok for the DS, I supposed, but sucks ass for the Wii (Nintendo themselves said you can use both).
I got it from a CAG for $25 a few months ago, and well, I'm not really too happy with it. Let's see all the problems I have (I'm on a wired network)...
I want to throw it out right now that this ONLY WORKS ON WINDOWS XP!!! If you have Windows 98, 2000, Vista, whatever, it won't work. Nintendo has no plans currently to get it working with Vista, so this thing isn't future proof at all.
On my old computer, I had it plugged into the USB port in the back (it only had USB ports on the back), and the Wii wouldn't recognize it, at all. And the Wii was maybe 10 steps away in the same exact room. I had to use the extended USB cable the provide to position it on the top of my computer at a weird angle - it's the only time the Wii would pick it up. And even then, sometimes it just straight up wouldn't connect.
With the DS, even if I went one room away (let's say, the bathroom) my connection would go from green to yellow (3 bars to 2). If I went across the room, forget about it! Had a hell of a time connecting and even if I did, lag city.
That's not even getting into the installation problems I had with it... and many others too. Prepare to see a ton of IPS errors... and that's if you're lucky.
On my new computer, I can't even get the thing to install, it freezes in the same place every time, no error message, just a straight up freeze. Nintendo had no solution when I emailed customer service.
I have to put it on my other computer, way across the house... the only one I can get the Wii to pick this up is if, and this is no joke, I use the included USB extension cord to hold the connector over my head at a 45 / 90 degree angle while my girlfriend downloads what we're getting from the Wii Shop... even then, the bar is only yellow.
The DS gets a shitty connection to it as well.
The Wii / DS detect it fine, but connecting to it to use as a different story altogether. I really doubt anyone's neighbor's is going to connect to this piece of shit Wi-Fi Connector, but if they do, there is a simple allow / deny prompt to stop that sort of thing. I don't think it's even designed for a computer to steal your bandwidth with this... it's just for the DS / Wii. Maybe I'm wrong, who knows.
I say take the $30 and invest in a REAL wireless network... this stupid thing has been nothing but trouble. Good luck to anyone who is deciding to use it... I hesitantly recommend it if you're just using a DS on it (as this seems to work the best) and I don't recommend it at all if you want to use a Wii.
I'm sure someone will say "I use it for both and it's perfect!" but the amount of complaints I've seen about this thing (very cryptic error messages, for one) has been staggering.