To add a friend on PS3 you have to use their PSN I.D, (my PSN I.D. is bronxsushi). Go to the far right side of the XMB and choose "Add a Friend". Enter the persons PSN I.D. to create a friend request. You might want to write something in friend request. Then send the friend request. Of course when the other person recieves the friend request they have to choose to accept the friend request for you to become their friend.