Static sample

Okay, I have neither the time nor the energy to whip up a tutorial right now, but I'll get something later. For now, here's the recipe:

REALISTIC MONOCHROME TV SNOW:

(You only ever need to do these steps the first time.)
Prep:
i.) Create a new document, 3px by 3px, Transparent background.
ii.) Using the Pencil tool, color the outside pixels black, and leave the middle one transparent. You'll have kind of a "donut" with a transparent center.
iii.) Select All, Edit : Define Pattern, and make this a pattern. This document can be discarded.

Cooking:
1.) Make a new document of the desired size, filled with black.
2.) Add about 25-35% Gaussian Monochrome noise to the background layer.
3.) Make a new layer atop the background.
4.) Fill the layer (Edit : Fill or Shift+F5) with the pattern you made in the Prep section. This should have "screened out" many of the noise pixels.
5.) Make a new layer, and "Copy Merged" the document into it, using Ctrl(Apple)+Shift+Alt(Option)+E.
6.) Use Image : Levels and tighten the tonal range on the image. Pixels should be near white or black, with few grays if any.
7.) Filter : Pixellate : Mosaic the layer at a mosaic of 2px square.
8.) The whites have all averaged out to gray again, so tighten the Levels again.
9.) Gaussian Blur at about 1.5 pixel radius.
10.) Apply an overzealous Unsharp Mask to re-sharpen the dots.
11.) Image : Levels again, and bring the right slider up so the dots become plump and rounded out.
12.) Add a 0-degree Motion Blur of about 5 pixels.
13.) You may wish to add a Hue-Saturation Adjustment Layer (in Colorize mode) and give a televisionly blue tint.

Result: This.