Don't be put off by the "DSI" in the title, it works with a good old DS Lite as well.
Very little to say about the product itself, it's a cheating device, great if (for example) you only have Pokemon Black and none of your friends bought White and you need to catch 'em all, you can use this device to see any Pokemon you like in the wild then catch it!
Basically works for any DS game, it comes with a USB Lead and software CD, simply use the software to download new cheats to your device. The codes come from www.codejunkies.com and it automatically selects European codes. The interface on the DS is slick and easy to follow, works perfectly, just stick your game in and start up and you'll be able to select codes and play from there. The PC software interface is a little clunkier so I wouldn't recommend it for young children but if you have even a basic understanding of computers it's fine.