You can either go to the icon Add friend or if you wish to add a person that you have recently played with, go to the icon that shows users that you have recently played with, highlight the users name and press triangle then add friend.
21/04/2008
Whoever appeals to the law against his fellow man is either a fool or a coward, whoever cannot take care of himself without that law is both. - Omerta (PSN: Wardog101)