Hi,
A quick Google search for "pitch range for harmonica types" gave a number of results. A quick scan of the first page of results gave a couple that looked promising:
http://www.angelfire.com/music/HarpOn/chrom.html
http://en.wikipedia.org/wiki/Harmonica
You may want to explore some of the other search results that come up for that search (or variations thereof).
Enjoy!
Sherry