Futurelooks publishes a Nyko Cord-Free Wireless Adapter for Wii Nunchuk review. The wireless nunchuk accessory sells for $19.99.

Quote from the review: "If you feel the same way as me and you get frustrated with the cord that connects the Wii Remote with the Nunchuk attachment, then you might want to take a look at the Nyko Cord-Free Wireless Adapter for Wii Nunchuk.
Yes, I realize it’s not the most creative of names, but it’s terribly descriptive. And it works exactly as advertised."
Read the full review on Futurelooks.