To create it, I have used blender, an open source 3d modeling program.
The instructions are quite simple (pictures help) and I hope you enjoy them
Here is the .blend file (you can modify it if you want)
Here is what the final product looks like: (more images on the last slide)
Step 1: The Image
In gimp (an open source photo editing software), I changed the text from
You shall not pass! ---- to ----- You shall not pay!
You can do this in pretty much any photo editing program
Step 2: The Face Plate
In the menu bar on the right, go to texture and select image --- find where you saved the Gandalf image and click open
You will not see the image on the shape but it is there, you will see it when you render it (f12)
Step 3: The Backbone
Step 4: Ta Da!
I changed the background color (of the sky) to emphasize the image
You can change the color of the sky by going under the little icon that looks like the globe on the right side (menu)