JP Allen believes that anyone can learn to play harmonica... site
From Mississippi, Adam Gussow's marvelous, full spectrum site
Rick Nielsen's extensive site on the "Mississippi Saxophone"
Mike Will's page is an excellent source for info on the diatonic harp.
Pat Missin not only plays, he is a scholar on harmonica history.
Extensive links, lessons, store and more.
Blues Harp Nation
Overblow fanatic Tinus Koorn plays everything on a single diatonic harp.
The Society for the Preservation and Advancement of the Harmonica
This site is for chromatic harmonica players; extensive resources.
Everything for amplifying harps; amps, custom wood mics, etc.
A site for collectors of antique, rare and collectible harmonicas
Harmonica Master Class specializes in educational materials for blues freaks.
Lots of personalized tips on playing the harmonica here
More than 13,000 harp tabs here
England checks in with "The Harp Players Harp Site"--deep stuff.
One of the most comprehensive harmonica sites with almost 500 links
A national directory of harmonica teachers
has a global perspective and a wide array of resources.