To Gentle and Soy, I bought the flight on the americanairlines.co.uk site. It cost the equivalent of €650 to Chicago plus the domestic flight return. This was about as cheap as I've seen it since all the fares seemed to rocket after April 1st and was €135 cheaper than the fare quoted by local travel agent.
However, a couple of things have cropped up. I've yet to be issued with my eticket email. Also, having looked closely at the itinerary, American have allowed 90 minutes for the transfer at Chicago on the outward trip and, more worryingly, less than an hour for the connection on the inbound leg of the journey. This surely is not enough, even at the quietest time in Chicago? I dont know who to contact about this, what can be done about it or whether there will be a penalty for changing flights. Is there an AmericanAirlines office in Dublin? In the recess of my mind I vaguely remember someone once saying that the airline is responsible for ensuring enough transfer time to make connections? Is this true? Above all, while I detest waiting at airports, the thought of missing my flight back to Dublin and having to await the next available flight, probably next day, is much worse.
As I understand it, American Airlines are codeshare partners with Aer Lingus on the Dublin-Chicago-Dublin route. There's a chance Aer lingus will operate the flight. I've never travelled with American before but I hope they at least will maintain Aer Lingus standards. Natural pessimist that I am, I just hope the trip goes reasonably smoothly.