First of all to use these skins you need to install both ICQ and ICQ plus plus on your computer.
Then you download the Zip file containing
your new skin. It can be placed in any folder in your computer, just
remember where it is).
Next, open ICQ Plus. (Go to ICQ main menu
- bottom left corner - and click on "Plus").
Select on the plus screen you will see a
button marked "Import". Click on it.
A browser will appear. Now remember
the name of the folder with the Zip file, go to it and retrieve your file.
Open the file - you should now see a preview
of the new skin.
Click "Apply" and all the files for the
new skin will be copied into a new folder within the C:\Program Files\ICQ
Plus\Skins directory and your ICQ display will change to show the new skin.
It's that easy.
Good luck