For switching 490mA I would use a ZTX851 transistor, base driven from the Arduino through a resistor of about 220 ohms. Simpler (1 less resistor) and cheaper than a logic-level mosfet. But for switching 1A, I would use a mosfet.
[EDIT: I might be wrong about it being cheaper, depending on your supplier. However, for switching 490mA, a BC337 is just about adequate - and they really are cheap.]