This glitch allows your characters to permanently have super strength, speed, defense, and any other power from the girl's magic menu:
Cast the spell of your choice on any single character, then quickly save your game after staying at the inn. When you restart your game, your character will have that power permanently. You can do this with as many power spells as you like, but some spells may interfere with others and cause previous powers to disapear.
If you want to re-enter the village you were banished from, you must have all 3 characters. Then, walk up to the man blocking the entrance, and rapidly push the SELECT button while holding the UP button against the man. Eventually you would will push your way through him, and be back into Potos Village. Note that this trick might not work in escaping from Potos Village, so make sure you have the Flammie Drum before you attempt this.
Anytime an enemy character casts an attack spell on you or an ally use the pygmy hammer / moogle belt on the character being attacked , do this twice before the spell animation ends. If done correctly the character will completly avoid taking any damage. This trick is very useful when you are fighting the Mana beast.