University of New South Wales (Australia)
University of New South Wales: Flute Acoustics
This site from the University of New South Wales describes, defines and gives an introduction to flute acoustics. A great site, it also provides many links to necessary information on the subject.
Library of Congress
Loc: Dayton C. Miller Flute Collection
More than 100 of Miller's 1,650 flutes and related flute artifacts/memorabilia, are available for viewing online. Catalog information and images of the instruments are available as well.