Instructions
Select the Mii Channel from the Wii main menu. Point the Wii remote at "Start" and press the "A" button.
Point your Wii remote at the screen to bring up the icons. Aim at the Wii remote icon on the right side of the screen and press the "A" button.
Choose the Wii remote you want to transfer your Mii to and press the "A" button.
Point at "Yes" and press "A" to format your controller for Mii save data.
Point the Wii remote at a Mii. Press the "A" and "B" buttons on the Wii remote at the same time to grab the Mii.
Drag the Mii to one of the save slots on your Wii remote.
Select "Save and Quit" to exit the Mii Plaza.