You will need a pair of 3D glasses or just home made ones ( YouTube - quick and easy way to make actuall 3d glasses ) ofc its recommended to buy them to get 3D effect like the movies in cinema on your World of Warcraft, follow the steps:
1. download driver from iZ3D Driver Download Page - iZ3D Drivers and Software for Stereoscopic 3D - iZ3D
2.run and install iZ3DDriverSetup.1.11RC2(1.99.0167)
3.Open iZ3d Control Center, tick enable stereo , from output choose Anaglyph(free) and red/cyan depending on your glasses
4.Go to profiles and choose World of Warcraft
5.Clock Browse and point where the wow.exe is
6.Run game and press Shift+* to get rid of the extra things on your screen
Ofc use your glasses and enjoy! its so addictive! (powerfull videocard is important) also its an anaglyph 3d