here i go again trying to sell my program...i do this a bit.
i went through a program called Cross Cultural Solutions. a little info:
1) more expensive then the link you have, but it includes up to $100,000 in health insurance while there (or something like that), 3 meals a day, ground transportation, little field trips
2) you have to pay a little extra to be insured a medical placement and not all locations can insure you one (called "intern abroad")
3) you stay in a house that is very safe with other volunteers
4) tons of placements (if you don't want to do medical), tons of start dates, lots of different countries, can stay anywhere from 2-12 weeks
5) from my experience, you are not surrounded by americans or even people that speak english
6) you volunteer about 5 hours a day in a very unstructured setting, where i went, they aren't used to volunteers, so you had to be very proactive in getting your hands dirty
7) you learn a ton about the culture as well-dance lessons, history lessons, language classes, trips to local villages
8) the intern abroad program in Guatemala is really picking up, a local doc talks to you a lot, you have a chance to visit local hospitals and see what they are like
9) examples of what people did in medical placements in my group: gave vaccines, took blood pressures, performed physicals, recorded pt. info (if you could speak spanish), took temps, helped deliver babies
that is all i can think of. i went to guatemala for 2 weeks. soooo much fun. feel free to ask any more questions if you'd like