Car Factory

http://www.gtacarkits.com/toyota_sienna_2004_2010_car_kit.php - installation instruction for iPhone, iPod, AUX, mp3 adapter into factory stereo of Toyota Sienna 2004, 2005, 2006, 2007, 2008, 2009 and 2010 model years. After installing the car kit you would be able to listen to your music player or iPhone through your factory stereo speakers and control your music through controls on the factory radio.
You can also use these video instructions for removing factory stereo.