I would suggest that you integrate directly with reputable organizations - it will place an abstraction between you and potential backlash for scamming. Also allows you to provide aid where you don't have direct reach already.
Another idea would be to integrate with hospitals/care givers directly, so you know the money is being spent properly. Hospitals/care givers will be less likely to scam you, as they can benefit in the long term and do have something to lose if caught scamming.
From a consumer standpoint, my main qualms when it comes to donations are (1) Control over where my money is spent, and (2) Knowing that my money spent is being put to good use. You guys have the opportunity to knock both those problems out.
Like I said above, transparency is the single most important thing to us, and we spent more than a year establishing our partnerships. If you have any specific questions about transparency and accountability, I am more than happy to field them here. We also have a ton of info on our FAQ: http://watsi.org/faq
The thing I am most proud of is that our Medical Partners are absolutely unbelievable. We have a Partners in Health Clinic (Paul Farmer's Organization), an amazing doctor in Ethiopia who our team doctor worked directly with (Dr. Rick Hodes), and a great NGO in Guatemala (featured on ABC).