Information on low latency trading (HFT) is hard to come by. Recently Low Latency posted the audio from the London Low Latency Summit. This set of interviews and discussions contains some of the best publicly available informations on topics such as FGPA Feed handlers, which inter-continental fiber links are used, some of the costs, typically deployments, metropolitan fiber networks and strategy deployment. If you are interested in the HFT space check it out.