3 links
How a Computer saved the world
acsa.net
Article from the American Computer Science Association about the history of Colossus (and IBM's involvement in WWII).
Nationmaster Encyclopedia: Colossus computer
nationmaster.com
The purpose, origins, and design of the world's first programmable digital electronic computer.
Take a Tour of Bletchley Park
lightstraw.co.uk
Information and photos on the Colossus rebuild project at Bletchley Park.