Instructions
Remove the battery cover on the Wii Remote. Verify that there are fresh batteries in the Wii Remote. Leave the cover off.
Turn on the Nintendo Wii. Open the SD slot located on the front of the Wii.
Press the "SYNC" button on the Nintendo Wii.
Press the "SYNC" button on the Wii Remote. The "SYNC" button is red and is located just under the battery compartment. Wait until the lights on the Wii Remote stabilize. Replace the battery cover.
Repeat that process for each Wii Remote you want to sync to the Wii.
Insert Mario Party 8 and select it from the Wii Channel Menu. When asked how many players you want to log in for that session, have all the players press the A button on their Wii Remotes.