Using Piezzo Electric buzzer 10V with an Arduino Lilypad USB
Your options:


Try it anyway with 5V: the buzzer might still produce loud enough sounds for your needs.
Use the line from the arduino to drive an "amplifying" stage (ex: 2N2222 in ON/OFF mode) - but this will also require a 10V source (like a step-up voltage converter)
Get a piezo that is designed to operate at 5V