Filters and Actions used in this tutorial can be found at ..
Insta Sketch Beta http://homepages.slingshot.co.nz/~mikefinn/action.html    
Plugin Filter Set 2 contains Illustrator - http://www.xero-graphics.co.uk/downloads.htm
Plugin Filter Set 1 contains Lithograph (see bang bang image last on this page)

Illustration Effect. Tips & Tricks using Photoshop.

Bang Bang- uses Illustrator and Lithograph filters.