Heres what i found on Aer Lingus and i know they have really good fall sales from JFK if your willing to go a little later. Hope this helps a bit.
From New York (JFK) Travel Dates One-Way Fare
to Dublin/Shannon July 9 - 31 From $415*
August 6 - 19 From $365*
August 20 - 30 From $277*
Tip: Make the most of your last vacation day. Aer Lingus' non-stop flight EI 109 departs Dublin at 5:20PM and arrives New York at 7:50PM (all times local).
10% Vacation Store discount will be applied in the shopping cart on the land portion of regular packages, accommodations, car rental and recommended products that are for travel now through 8.31.06. 10% discount does not apply to airfare, insurance, taxes and fees. All travel must be booked by 7.17.06 to honor discount.