werneck

Haiti is not only within the earthquake zone, but any natural disaster possible. Flooding was the major catastrophe before this year's earthquake.
Unfortunately, solutions from the developed World are out of range for poor countries, also. It is extremely important to consider local materials and expertise, or you will only reach a small part of the population.
I would call attention to a solution commonly found around the Amazon river: houses made of local wood, rasied above the river. If we transport this idea to Haiti, we would have the following benefits:
1. Easy construction: local materials and expertise available;
2. Easy maintenance: raised structures allow access from the the outside;
3. Low cost;
4. Multi disaster resistance: it may not cover hurricanes, if not well done, but it will get through the floods, which are quite common and the earthquake.

Cheers!