It is correct to note that new US Immigration facilities will be in place at Terminal 2 in DUB when that facility opens (eventually!). Terminal 2 will not be specifically for US bound flights but will have full immigration AND customs preclearance facilities which will mean no further queues on the US side and the ability to fly directly to "domestic" US airports and teminals (i.e. ones without immigration and customs facilities). Further information about the Dublin Airport development can be found here:
http://www.dublinairportauthority.co...nt/Terminal_2/
FYI - full preclearance facilities should be available at SNN within the coming year if a planned extension to accomodate the customs pre-clearance and associated baggage facilities is approved. (and in SNN queues are short
)
Hope this helps ...
Andrew