Here's some info on a NACA duct,
http://en.wikipedia.org/wiki/NACA_duct which is fairly straight forward as it talks about the Pack ram air inlets.
If you look up NACA wing you better ask Joe Sutter as it's all engineering talk.
http://www.geocities.com/vienna/2616/node57.html
http://www.google.com/search?sourcei...en&q=NACA+wing
SMOC