1. Find the icon you want to use, and
open its info window (File > Get
Info, or command-i)
2. Click once on the icon in the top left corner of the Info window
3. Copy the icon (Edit > Copy, or command-c)
4. Choose the file or folder which you wish to place the new icon onto.
5. Open the info window for that file or folder
6. Choose the old icon in the top left of the info window
7. Paste (Edit > Paste, or command-v) the new icon into place
8. Et voila...Hopefully.
LEGAL DISCLAIMER
The icon must not be used for commercial
purposes. These icons can only be distributed as freeware, and may
not be redistributed, sold or exchanged for any goods or services.