Regions:  Outer Ear, Middle Ear, and Inner Ear

Parts and their Function:
Pinna (Ear Flap) - collect sound
Auditory (Ear) Canal - provides a passageway for sound traveling from the pinna to the eardrum, and it protects the ear from infection
Eardrum - vibrates when impacted by sound waves that have traveled through the auditory canal, and then transfers those vibrations to the middle ear
The Ossicles - three tiny bones called the hammer, anvil, and stirrup due to their shapes (or the malleus, incus, and stapes). These bones transfer the vibrations of the eardrum to the inner ear.
Hammer (Malleus) - first bone
Anvil (Incus) - second bone
Stirrup (Stapes) - third bone
Eustachian Tube - lets fluid drain down the throat and equalizes pressure on either side of the ear drum
Cochlea - converts physical vibrations into electrical impulses
Auditory Nerve - pathway that transfers neurel signals from the cochlea to the brain.

Picture from Glenbrook South High School: The Physics Classroom found at
http://www.glenbrook.k12.il.us/gbssci/phys/Class/BBoard.html  I highly recommend going to this site and taking the tutorials.  They are well construsted and structured!

Information from The Sounrdy found at http://library.thinkquest.org/19537/Main.html
Another excellent site!