d2k73,
You could put your question to the forum at
AskAboutMoney.com for some financial advice, but you'll probably be told that since none of us have a crystal ball, all advice on the direction that the dollar-euro rate will take should be taken with a pinch of salt.
As regards more generic advice (assuming you already have a significant amount saved towards your trip to Naples), if you're happy with the value of the training against the current exchange rate, you could hedge your bets and convert some of your euro's to dollars now. If the rate continues to slide, you'll be glad you did it. If the exchange rate rises again, you'll probably kick yourself but at least you have an accurate budget (i.e. the euro costs) to work from.
Another potential factor to bear in mind is the cost of oil. Recent falls in oil prices are being off-set in Europe by the strengthening dollar. If oil continues to decrease in price, the dollar cost of flying the US may fall sufficiently to make it still worthwhile despite a weakening euro.
Food for thought....