Toyota Repair: Toyota Sienna whining, toyota sienna, alternator

Question
I have a 2001 Toy. Sienna.  When I shift into drive (it doesn't happen when I am in reverse, backing out of my driveway)and have my air conditioning on I hear a loud whining sound.  It used to only last a few moments and then stop, but now it continues for quite some time.  When it is making this noise, if I turn the A/C off , the noise stops, but starts immediately when I turn the A/C back on.

Answer
The noise may be caused by the alternator, toyota had issued a service bulletin that involves replacing the alternator with an updated version, with the a/c off and all other lights,fan, dome lights, radio etc on, does it still make the same noise? If so, the alternator is the cause, if the noise is only there when the a/c is on with everything else off then you should consider that there may be a problem with the A/C compressor.