To do this you need Picasa or Photoshop. Luckily I have access to Photoshop so I was able to do this colouring book on there.
All you do is upload the photograph that you want then change the filter to sketch then photocopy.
You then amend the detail until you are happy with the results then Print!
It is possible to do this on Picasa but I was not as impressed with the output
In Picasa under the special edits you click on Pencil Sketch then move the sliders till you find the best output then print.
I hope that this has come in helpful.