According for Charger's
product page, it's "100-240V~50/60Hz 0.5A; Output: 5.0V 1.8A" - so yea, international like most gadgets (except consoles). Doesn't seem to have exchangeable heads though, I've only seen that included on Blackberry chargers and some laptop chargers.
In a pinch, people say you can still USB charge slowly with a normal USB cable.