Hey dudes, don't forget that if you have an older psx unit, you also have the option of using a Game Enhancer type cartrige. Only difference is that you have to use an original(any game) to boot, and then when the motor stops, swap your copy and press start. Generaly you can use Gameshark(R) codes too, as it's basicly the same device, but with slightly different programing.
Just check the back of your PSX to see if this is an option for you. If you have a scph-9xxx you're out of luck, cause Sony eliminated the port on this model. Older Models(scph-1xxx,5xxx, & 7xxx all have the port.)
Some people don't like having to swap discs, but if you don't know how to solder or can't find someone reilable to do it for you, this is your best option as it is truely plug and play!