Just documenting this here since it apparently is not to be included in the official docs.
Previous version of the Servo Library Write function docs:
Writes a value to the servo, controlling the shaft accordingly. On a standard servo, this will set the angle of the shaft (in degrees), moving the shaft to that orientation. On a continuous rotation servo, this will set the speed of the servo (with 0 being full-speed in one direction, 180 being full speed in the other, and a value near 90 being no movement).
Parameter values between 544 and 2400 passed to the write method will be interpreted in microseconds (uS), exactly the same as the writeMicroseconds method.
servo.write(angle OR microseconds)
angle: in degrees, from 0 to 180 microseconds: the angle value in uS, from 544 to 2400
Arduino: We like it when you do it our way.