Double click the .atn file and PS should add the action to your library automatically. At least this works in newer versions of PS.
Alternative method: 1. Put the .atn file from the zip in a directory of your choice. It does not need to be in the Photoshop directory. 2. Choose Load Actions from the Actions palette menu. 3. Select the action set file from the directory you saved it. 4. Click Load. 5. Have fun.
------------------------ Update 05.10.2010
cleaned up dialogues reworked contrast enhancement preview image polished
Update 15.06.2007
added a contrast enhancement (tested in CS2/CS3/CS4) minor fixes ------------------------
I tried it a few times but keeps saying files arnt found when i use it in ps. I uploaded the file and such to ps but there are a few stps that dont work. Like eye color and such. D: