vin mentioned, what is that?
VIN, Voltage IN. The voltage applied to the DC barrel jack. Usually between 7 and 12 volts.
Normally you would split the power to the servo and the Arduino, servos like about 6v which unfortunately is not enough to drive the Arduino so that may mean two power supplies.
If you have power then two plug packs, for batteries maybe a 7v2 battery directly to the Arduino and regulated down for the servo.
EDIT: That servo can operate up to 7v2, so it looks like you can use a battery or single plug pack for both.
Rob