[quote name='Zapster']Yeah thats what I am worried about. I am worried that I will buy a used game, go online to sign up the used game, and get rejected because the previous owner already registered the same game online.[/QUOTE]
Zap, you don't have to worry. If you were to sign in you are signing as your own account. It does not matter who had the game before or how many people had the game before. There is no special code required to play online for any PS3 game. Its not like PC games.