Halftone materials?

I'm trying to figure out a way to create some comic book style halftone effects. I'm currently experimenting with sketch and toon, but not getting the best results. Anyone know of any tutorials or materials already available to achieve a halftone effect? I'm coming up empty when I ask google.

At the moment I'm having to process the video in photoshop, but processing multiple passes is a pain.

I'm using C4D R13

Thanks,

Chad

It wasn't quite getting what I wanted, but it was close, I needed more than just putting spots on an object, though I like the way it works with lights and shading. I ended up processing footage in photoshop using the Halftone effect and using this little particular preset: http://www.motion-graphics-exchange.com/after-effects/Particular-Halftone-E...