Hi,
Just a quick post as I've not got around to an intro yet, but the Bombe was the device that found the possible keys to decode with (once the code had been part broken by the code-breakers themselves).
To decode the messages, a number of British Typex cryptos were modified to operate like Enigma machines. This allowed them to decode the messages even though they only had a small number of actual Enigma machines, using the keys that had been found using the Bombe.
There's a photo of a modified Typex on this site -
http://www.jharper.demon.co.uk/typex1.htm
TTFN
Lauren