How to use ICQ skin:
Download ICQ Plus, install it. Once you have ICQ. Plus, you will be able to use the skins. Then, after downloading the ZIP files, unzip them into the directory "C\ProgramFiles\ICQPlus\Skins\Skin_name\" or whereever the directory for ICQ skins are. Replace "Skin_name" with the name of the ICQ skin. It will appear in the ICQ plus dialogue box. 

To use a skin, go to ICQ's main menu, click on ICQ Plus, and the menu will appear. Select the skin's name. A preview will appear. Click OK to use the skin, and resize the ICQ box accordingly so that your skin looks okay

Programs needed: ICQPlus, ICQ (duh), and WINZIP.