You need to buy third party software, such as Codebreaker, Action Replay MAX, and Gameshark, for your Playstation 2. You put the disk in your PS2, enter/select the codes, and then it will prompt you to eject that disk and insert the game that the codes are for.
A lot of them aren't being made anymore, so they could go on the expensive side, but you can always get a used one. Look on Amazon.com, or anywhere else you might buy stuff.
Comments on Profile Post by Labrys