Nyko's wireless nunchuk peripheral was awarded CNET's best in gaming at CES this year. The wireless nunchuk "connects" through a dongle attached to the bottom of the Wiimote (seen above) and runs off two AAA batteries which allegedly provide 30 hours of use; the cost is $30 and should be out by late January or early February.
Nyko actually introduced many new peripherals at this year's CES. Coincidentally this would be the second year in a row that Nyko introduced a relatively useful product for the Wii, last year they came through with the Wiimote charge station which we're told has sold very well. Of course, not every Nyko product has to be reasonable, the Wii Party station is still one of the most atrociously awesome things we saw in the past year.