Some people probley already know about this,but never the less..

Debug Mode
NOTE: This code requires a GameShark.

This code is by far the coolest thing you will ever see. First enter the code "8009A05C 0041" into your GameShark. Start-up FF7 with the first disk. Choose "New Game". Instead of the normal opening CG movie you will appear in a room filled with Japanese symbols. IMPORTANT! Turn off your Gameshark after you are in the room.

Walking onto these symbols will transport you to other rooms where you can go to any point in the game, watch the CG movies,get exp, and gain a complete set of materia among other things. You can also talk to the man in the bottom left corner to adjust other settings.

You can also have sephiroth in your party

You don't need to use the debug mode to get Sephiroth in your party. There's a code that will allow you to put three of him in your party from any point in the game. Also, any other character, including three Aerises.

I still have this code. I'm not sure if it's still around on the web.

56K ARMAGEDDON GLOTY!!!!!