Look into Tax Breaks
Yes, you're volunteering, but there's nothing wrong with getting a financial benefit out of the whole thing. Sure, you'll have to pay for your flight and possibly parts of your stay, but provided your working at least 40 hours at a non-profit, you'll be able to write off many of your expenses [source: Tuttle].
If you've already done the research into the organization, you should know if it's a for-profit or non-profit. As long as it's non-profit you'll be able to write-off your plane ticket, travel expenses and any boarding expenses you incur.