Seconded (thirded? fourthed?) I'd also add the Information Age gallery at the Science Museum in London, which covers from the telegraph to Arm and the modern d

Seconded (thirded? fourthed?) I'd also add the Information Age gallery at the Science Museum in London, which covers from the telegraph to Arm and the modern day, its aimed at a more mainstream audience than Bletchley but is free and well worth a look.