From Wikipedia: "Telegraph systems all over Europe and North America failed, in some cases giving telegraph operators electric shocks. Telegraph pylons threw sparks. Some telegraph systems continued to send and receive messages despite having been disconnected from their power supplies." I have also read that paper on their desks caucht fire.
If such a thing happens today (and it will happen at one time or other, it's overdue), the implications would be massive. Computers world wide will be knocked out, satellites gone, communication breaking down. Financial systems might also break down, causing mild confusion

http://en.wikipedia.org/wiki/Solar_storm_of_1859