Hey guys, does anyone know how to create sunbeams similar to how it was done in this video?
Maybe with Unity Pro and Image Effects you can get it 
Or you can do a mesh and apply a shader or a texture semi transparent.
Also you can add particles if you want dust.
I played a bit with emulating your sunbeams using a mesh and a texture. The result were not too bad. A real artist would do a better job. I created a material using the Particles/Alpha Blended shader, and attached this texture:
I played some with the color in the material…brought down the alpha, moved a bit more from grey to white in the color. I put the material on both a plane and on cylinder. The cylinder looked okay if I “hid” the top above the ceiling, and the bottom below the floor. A custom tapered cylinder mesh without a top or bottom would work better.