The Logitech Cordless Keyboard is a wireless peripheral for the Wii. Its main function is for websurfing, file-sharing and searching on the various Wii internet channels.
Although its highly responsive, incredibly durable and reliable, with a sleek, cool, slim, white ergonomic design and brilliantly economical battery life, its very, very expensive. This thing will run you in the market of about thirty pounds of Amazon, and since they're not that popular and quite difficult to come by, full price is likely what you'll have to pay.
There's not really any real reason to buy this, despite its excellent functionality, since there are cheaper counterparts for the Xbox and PS3 if you have them, and of course, there's laptops and PCs to consider. Bearing in mind that the Wii isn't actually a HD ready console, this isn't really the best investment. Needless to say, apart from Youtube channels and BBC iPlayer, there's not a massive amount of things you can even use a keyboard for on the Wii, and certainly nothing that you can't do on any other next-gen consoles.
Anyway, if you do actually have a good reason to use a keyboard in conjunction with the Wii, other than entering player usernames and light browsing, then this is definitely the best out there. Its got all the buttons pertinent to a regular wireless keyboard, obviously, and can be easily used in conjunction with the Wii, with no hacking required. Its simple plug and play interface and fantastic design alone push it ahead of the competition in terms of other Wii Keyboards. Although there's not really any great necessity for this particular one to be wireless.
Logitech, in my experience has been a damn reliable brand for this kind of thing, and the Cordless Wii Keyboard is no exception, although I am a bit puzzled as to why it wasn't named the "Wiiboard."