Air Serv's office is in Washington DC or Virginia, can't remember. They'll be the ones who interview and accept you. You'll want to be pretty conservative. A christian upbringing is good, as some of the big shots are ex MAF. (although out in the field, it can be good fun, Coco Jambo's and Le Chalet in Goma for starters)
They'll post you somewhere around the world. Check your policies are paid up. You can see their website of destinations, Afganistan, the Congo, etc. The pay sucks, but your overheads are low.
Ray at Entebbe does not do interviews. Also don't get excited about flying a B200. It'll be a twin Otter or Cessna Caravan to start with. Then a B90. Having some bush flying will be a credit.
And yes, you do go to some hot zones. Go to a search engine and look up Shabunda in the DRC. Lovely little place, although the militia are letting MSF (medisans sans frontier) in.
Good luck