To install - after you have downloaded the file, unzip it to the following directory:
C:\Program Files\Adobe\Photoshop 6.0(or 7.0)\Presets\Brushes (i.e., your photoshop brushes folder). Then open Photoshop and from your brush menu, choose "load brushes" fig.1 and from the list which will open, choose the brush(es) you would like to load. Once done, choose the brush you have just added to begin using it.