Instructions
Press the "Triangle" button on the "PlayStation 2" controller to open up the main menu screen.
Scroll down the list using the directional buttons and select "Equip." Press "X" over "Equip" to open up the equipment menu.
Press the "L2" and "R2" buttons to scroll through your list of characters until you find the character for which you wish to change the weapon.
Press the "X" button over the "Weapon" text to view a list of all available weapons you have in your inventory for the character. Use the directional pad to select the weapon you wish to equip.
Press the "X" button once you have selected a weapon, to equip it.