Thanks Elias for the comments. I made this using Blender and its new Freestyle renderer being integrated into Blender.
maximecurioni.com/freestyle/
The Freestyle renderer is still not part of the official releases of Blender, so you need to download a build having the Freestyle renderer at graphicall.org/builds/
The solid strokes (outlines) were drawn by Freestyle (with a slightly modified qi0.py style module), while the halftones were generated by a PyNode script, which is available in a post of mine in the BA PyNode cookbook thread:
blenderartists.org/forum/showpost.php?p=1234519&postcount=147
You can also take a look at still images of the 3D model in the following post:
blenderartists.org/forum/showpost.php?p=1232711&postcount=145
Recently I made an entry to the Blender 2.49 splash screen contest using the same 3D model and rendering techniques. In the following post, you can find a screenshot of Blender showing a material node using the PyNode script, as well as the compositor for combining the strokes and the halftones:
blenderartists.org/forum/showpost.php?p=1354984&postcount=97
The topics to be covered by a step-by-step tutorial are too broad for me to write donwn. I hope these pieces of information would help you get what is going on behind the scene. Free free to ask me if you have questions.