Instructions
Local Multiplayer
Hold the "1" and "2" buttons on the WiiMote you want to use for Player 1 while the title screen of "Call of Duty: World at War" is displayed.
Repeat the process for the second WiiMote. One WiiMote should now have the blue "1" LED lit, and another the "2" LED.
Select "Campaign" with the Player 1 WiiMote. Use this WiiMote to select "2 Player" to register Player 2.
Internet Play
Select "Multiplayer" from the main menu of "Call of Duty: World at War."
Choose "Host," then have the second player choose "Private Match."
Have your friend select "Private Match," then choose your hosted game. As soon as your friend selects the match you are hosting, they will be added to this match.