If you don't mind changing planes, you may want to consider flying to MacArthur (ISP), Islip US via Philadelphia, Houston on US Airways and Continental.
Go ahead and book your flight to Islip NOW!
In order to get the lowest available airfare, book your flight to Islip as early as possible, since the cheapest seats are booked months before departure. If you are flexible depart on the first Tuesday of the month, as there are usually some great deals and discount airline tickets on offer.