You will need Photoshop and possibly WinZip (if the files are .zipped up).
1. Save, Download (and extract if necessary) the brush file.
2. Locate your Computer's HardDrive (C:/ Drive)
3. Open up "My Programs" and find the "Adobe" folder.
4. Open up your version of Photoshop (Photoshop 7, CS2, CS3, CS4 etc)
5. Open up the "Presets" folder and find the "Brushes" folder.
6. Drag and drop the .abr brush file into the "Brushes" folder.
Use if you want to test the brushes without saving them to your computer or having to hard install them to your brushes folder. You may need Winzip or another extraction program to launch .zips
1. Click the download link to the brush.
2. Instead of saving click "Open"
3. Open up the zip if necessary
4. Double click the .abr file and the brushes will be loaded temporarily into Photoshop.