Here is a good link
http://www.bowhunting.net/NAspecies/wildturkey.html

Best arrow shot is the button of theTom's Fan in full strutt - or a shot at the wing base if facing you side ways. Or I have seen video of those Guillotine arrows taking the head clean off if you want a real challenge.

this give you an anatomy look
http://www.shop.com/+-a-turkey+anatomy-p45513219-k36-st.shtml

this gives you an inside look
http://en.wikipedia.org/wiki/Bird_anatomy

and this one is very good as it gives you three places to aim

http://www.wingsupply.com/shop/Scripts/article1.htm

JW