I made something similar to this during my photo school days, but it used foamcore and double stick tape and was not nearly as cool (or sturdy). That said, I LOVE this idea for a simple and creative way to display photos, prints, and art -- for cheap!
The main ingredient here is plastic cap molding, which you can get at just about any hardware store. Once you get your hands on some of that, check out Photojojo for the full supply list and instructions!
Material : plastic