How can I program a motor to rotate towards the source of sound?
To detect the highest sound you can use this code. It would help if you posted a picture of your bot, but with a general idea here you go:

FOREVER loop
{

if RightSensor &gt; Left Sensor :
    if RightSensor &gt; MidSensor :
        highest = RightSensor
    else :
        highest = MidSensor
else:
    highest = LeftSensor

if LeftSensor is the highest:
        turn left
if RightSensor is the highest:
        turn right
if MidSensor is the highest:
        do not turn
}