Audio Systems: adding MP3 to factory system, auxiliary input adapter, chevrolet 2002

Question
2006 Silverado w/ Bose sound system, including 6 CD changer. I would like to use an MP3 for audible books and play through the factory system. Is there an auxliary input on this system? There appears to be some sort of port next to the CD changer. Your help will be appreciated.  

Answer
there are two way
auxiliary audio input (radio must have a BAND and CD/AUX button

http://www.oemautosound.com/pc-296-83-piegm12-aux-chevrolet-2002-2007-auxiliary-...

or this will let you add any audio source and Ipods

http://www.oemautosound.com/pc-239-139-pie-pa11-gm-chevroletchevy-2000-2007-to-i...