Computer History Museum
http://www.computerhistory.org/
Our mission is to preserve and present for posterity the artifacts and stories of the information age. As such, the Museum plays a unique role in the history of the computing revolution and its worldwide impact on the human experience.

Internet Archive
http://www.archive.org/index.php
The Internet Archive is building a digital library of Internet sites and other cultural artifacts in digital form.   Like a paper library, we provide free access to researchers, historians, scholars, and the general public


Larwe.com
http://www.larwe.com/museum/
A site devoted to vintage computers and video arcade games, owned by Lewin A.R.W. Edwards.

PC History I
http://www-03.ibm.com/ibm/history/exhibits/pc/pc_1.html
PC precursors manufactured by IBM.   From the IBM History Exhibits

PC History II
http://www.pc-history.org/
PC precursors manufactured by other companies.   A tribute to the work of Stan Veit, a pioneer of personal computing.

PC History III
http://www-03.ibm.com/ibm/history/exhibits/pc25/pc25_intro.html
The first real PC: the IBM Model 5150.  From the IBM History Exhibits