1. Set the base type in the desired font. We used ITC American Typewriter font, medium. (Layer #1 at left.)
2. Roughen the type - Duplicate the layer, (layer 2 at left.) then Filter->Pixelate->Fragment to add a bit of roughness around the edges. (Various methods abound, see January, DT&G 9701 &Type! column.)
__ You can do this several times to achieve the degree of 'roughness' you like. We did it twice here. The roughness will smooth out later, so don't be alarmed.