Check out this great article about traveling healthy by Sid Kaplan.
Most of Sid’s tips are pretty basic–wash your hands often, don’t drink suspicious water, get any necessary vaccinations before traveling to an exotic destination.
These things will help keep an already healthy person healthy on the road, and may mean the difference between an awesome vacation and a miserable hotel-room-only failure of a trip for those of us who already have health problems.
I know nothing about IAMAT (International Association for Medical Assistance to Travelers) yet. But it seems like contact with this organization would be indispensable to a disabled traveler who’s planning a trip to an international locale!