China Biographical Database Project
Based at Harvard University, this database has biographical information for over 300,000 individuals.  CBDB is searchable in English and Chinese.

Policing the Shanghai International Settlement, 1894-1945 
*Available to current students, faculty and staff only
An archival collection of documents from the British-run Special Branch of the Shanghai Municipal Police based in Shanghai's former International Settlement.

Political, Economic, and Military Conditions in China: Reports and Correspondence of the U.S. Military Intelligence Division, 1918-1941 
*Available to current students, faculty and staff only
Published by Gale.

The U.S. "Tiananmen Papers"
A collection of digital documents from the National Security Archive.

Visualizing China
Funded by JISC (Joint Information Systems Committee of the UK), this site hosts a digital collection of historic photos of China.