take a look at ayatoweb.com. he has a few tutorials there that may be very helpful… in particular examples 49, 50 and 52.
also a couple of free effects, retrodots and halftone (part of pete’s plugins) that may help you ‘halftone’ your image.
both of those will only generate a halftone patten based on luminance, if you need a color halftone, you may need to find a different effect. or, separate the channels of your image using channel combiner on separate duplicates of the image setting each r, g or b channel to luminace only. then applying one of the halftone effects to each layer, modifying the angle as needed. then colorizing the halftone dots to the appropriate color.
or possibly do it in photoshop, which will give you a cmyk dot pattern, which would be more like a newspaper.
Kevin Camp
Designer – KCPQ, KMYQ & KRCW