AlanTuring.net: The Turing Archive for the History of Computing
Claiming to contain "the largest Web collection of digital facsimiles of original documents by Turing and other pioneers of computing," this site includes information about Turing and his work on code breaking and interest in AI, computational complexity, and connectionism. In addition, there are related reference articles, and a link to The Turing Digital Archive that contains unpublished personal papers and photographs.
Computer History Museum
The Computer History Museum is a real and virtual museum that preserves and presents important artifacts and documentation about computing. Its online collection includes photographs of the artifacts, documents, exhibits, the hall of fellows, a timeline of important events from 1945 to 1990, and a discussion forum.