I liked the comicbook effect so much, I’ve turned it into a Photoshop Action. Just download it here and drop it into your \Presets\Photoshop Actions folder in your Photoshop directory. Start Photoshop and load Greywulf.atn from the Actions pallette – Comicbookify is right there. Load an image and hit Play.
Here’s a few more samples.
It works with real photos too! Give it a try, and post your results in the comments.