I don't understand how people can be so useless with computers..
on vista, the Add-on folder is located at :-
Computer - Local Disk - Program Files - Bohemia Interactive - ArmA - add-ons
if the add-on you have just downloaded has any PBO files, you extract the PBO files to the add-ons folder (using Win Rar)
But always read the readme
incase you have to do it a different way..
-I wasn't talking to you guys above, just for anyone else if they have a simple problem, or who are new to the whole PBO business-
-also, if anyone has a problem which they REALLY don't understand, post what it is you are downloading and what your problem is, But only ask me if you have Vista as I don't know squat about XP-