Charles
Babbage Institute http://www.cbi.umn.edu/
The Charles Babbage Institute is a research center at the University
of Minnesota dedicated to the preservation of the history of information
processing.
IEEE
Annals of the History of Computing http://www.computer.org/annals/
This site chronicles significant historical contributions and
their impact on computing and society today.
Mechanical
Calculating Machines http://www.webcom.com/calc
This site by by Erez Kaplan, is all about mechanical calculating.
It includes chronological description, classification and pictorial
view (dozens of photographs), books, organizations and much more.